Introductory Guide
MedDRA Version 23.0

March 2020
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Notice to Reader

Notice to Reader
This Introductory Guide is written in English and is intended only for use with theEnglish version of MedDRA. Additional Introductory Guides have been developed tosupport languages other than English and are included with their specific translation
copies.
The Introductory Guide is intended for use in conjunction with the MedDRA Browsers,
available with each MedDRA subscription.
Changes which are version specific or changes in documentation may be found in the
What's New document. This document is included with the MedDRA release and isalso posted on the MSSO Web site under Support Documentation.
The MedDRA terminology is maintained under an ISO 9001:2015 registered quality
management system.
***

In MedDRA Version 23.0, several complex changes worthy of note were implemented in
SOC Congenital, familial and genetic disorders to refine the hierarchical placement ofgenetic term concepts. Descriptions of the following modifications have been
incorporated into the text of Section 6.3.1 of this document:

HLGT Chromosomal abnormalities and abnormal gene carriers was replacedwith new HLGT Chromosomal abnormalities, gene alterations and gene variants
to represent that SOC Congenital, familial and genetic disorders is intended tocover gene concepts, whether they are acquired or congenital.



HLT Gene mutations and other alterations NEC was added to new HLGT
Chromosomal abnormalities, gene alterations and gene variants, and former HLT
Acquired gene mutations and other alterations was merged into the new HLTGene mutations and other alterations NEC. This new HLT groups together all
gene conditions and alterations such as overexpressions, rearrangements, andmutations, regardless of whether they are congenital or acquired, and separates
gene concepts from chromosomal concepts which are represented in other HLTs
of SOC Congenital, familial and genetic disorders.



New HLT Genetic polymorphisms was added to HLGT Chromosomal
abnormalities, gene alterations and gene variants. The creation of an HLT for
genetic polymorphisms, which are considered as gene variants rather than genealterations, aids in the coding and retrieval of these concepts.

Existing Preferred Terms were moved or realigned as appropriate in accordance withthe revised hierarchical groupings in SOC Congenital, familial and genetic disorders.

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Acknowledgements

Acknowledgements
MedDRA® trademark is registered by ICH.
The following sources of information are also acknowledged: Diagnostic and Statistical
Manual of Mental Disorders, Fifth Edition (DSM-5) Copyright 2013 American
Psychiatric Association. ICD-9-CM, International Classification of Diseases, Ninth
Revision, Clinical Modification, Copyright 1998 Medicode, Inc. COSTART Thesaurus
Fifth Edition, Copyright 1995 US Food and Drug Administration (FDA). Hoechst
Adverse Reaction Terminology System (HARTS), Copyright 1992 Aventis Pharma.
WHO Adverse Reaction Terminology (WHO-ART), Copyright 1998 World HealthOrganization Collaborating Centre for International Drug Monitoring. Japanese Adverse
Reaction Terminology (J-ART) is a product of the Ministry of Health, Labour andWelfare (MHLW). LOINC is a registered trademark of Regenstrief Institute, Inc.
Lanoxin is a registered trademark of GlaxoSmithKline. Merriam-Webster is a
registered trademark of Merriam-Webster, Incorporated. Merriam-Webster Online
Dictionary copyright  2005 by Merriam-Webster, Incorporated. Dorland's Illustrated
Medical Dictionary, copyright  2004, W. B. Saunders, an Elsevier imprint.
Disclaimer and Copyright NoticeThis document is protected by copyright and may, with the exception of the MedDRA
and ICH logos, be used, reproduced, incorporated into other works, adapted, modified,translated or distributed under a public license provided that ICH's copyright in the
document is acknowledged at all times. In case of any adaption, modification ortranslation of the document, reasonable steps must be taken to clearly label, demarcate
or otherwise identify that changes were made to or based on the original document. Any
impression that the adaption, modification or translation of the original document isendorsed or sponsored by the ICH must be avoided.
The document is provided "as is" without warranty of any kind. In no event shall the ICH
or the authors of the original document be liable for any claim, damages or other liability
arising from the use of the document.
The above-mentioned permissions do not apply to content supplied by third parties.
Therefore, for documents where the copyright vests in a third party, permission forreproduction must be obtained from this copyright holder.

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Table of Contents

TABLE OF CONTENTS
1.

2.

3.

4.

INTRODUCTION .................................................................................................. 7
1.1

BACKGROUND .............................................................................. 7

1.2

ADOPTION OF MEDICAL TERMINOLOGY AS AN ICH TOPIC ... 8

1.3

DEVELOPMENT OF THE MEDICAL DICTIONARY FORREGULATORY ACTIVITIES (MedDRA) TERMINOLOGY ............ 8

1.4

IMPLEMENTATION OF THE TERMINOLOGY .............................. 8

1.5

SCOPE OF THE TERMINOLOGY .................................................. 9

1.6

INCLUSION OF TERMS FROM ESTABLISHEDTERMINOLOGIES ........................................................................ 10

1.7

EXCLUSION CRITERIA ............................................................... 10

STRUCTURAL ELEMENTS OF THE TERMINOLOGY ..................................... 11
2.1

EQUIVALENCE ............................................................................ 11

2.2

HIERARCHICAL ........................................................................... 11

LEVELS OF STRUCTURAL HIERARCHY ........................................................ 13
3.1

LOWEST LEVEL TERMS ............................................................. 13

3.2

PREFERRED TERMS .................................................................. 14

3.3

HIGH LEVEL TERMS ................................................................... 14

3.4

HIGH LEVEL GROUP TERMS ..................................................... 15

3.5

SYSTEM ORGAN CLASS ............................................................ 15

3.6

STANDARDISED MedDRA QUERY (SMQ)................................. 19

RULES AND CONVENTIONS ADOPTED IN THE TERMINOLOGY(INCLUDING PRESENTATION AND FORMATTING OF TERMS) ................... 20
4.1

SPELLING .................................................................................... 20

4.2

ABBREVIATIONS ........................................................................ 20

4.3

CAPITALIZATION ........................................................................ 21

4.4

PUNCTUATION ............................................................................ 21

4.5

SINGLE WORD VS. MULTIPLE WORD TERMS ......................... 21

4.6

WORD ORDER ............................................................................. 22

4.7

MedDRA CODES ......................................................................... 22

4.8

BODY SITE CONSIDERATIONS IN MedDRA ............................. 22

4.9

NUMERICAL VALUES ................................................................. 23

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5.

6.

4.10

AGGRAVATION OF UNDERLYING CONDITIONS ..................... 23

4.11

NOS AND NEC TERMS ............................................................... 23

4.12

GENDER SPECIFIC TERMS ........................................................ 24

4.13

HIERARCHY NAMING CONVENTIONS ...................................... 24

PT AND LLT NAMING CONVENTIONS ............................................................ 26
5.1

GENERAL WORD USAGE .......................................................... 26

5.2

GENERAL SEARCH STRATEGIES............................................. 29

SYSTEM ORGAN CLASSES............................................................................. 30
6.1

BLOOD AND LYMPHATIC SYSTEM DISORDERS..................... 31

6.2

CARDIAC DISORDERS ............................................................... 32

6.3

CONGENITAL, FAMILIAL AND GENETIC DISORDERS ............ 33

6.4

EAR AND LABYRINTH DISORDERS .......................................... 35

6.5

ENDOCRINE DISORDERS .......................................................... 36

6.6

EYE DISORDERS......................................................................... 37

6.7

GASTROINTESTINAL DISORDERS ........................................... 39

6.8

GENERAL DISORDERS AND ADMINISTRATION SITE
CONDITIONS................................................................................ 40

6.9

HEPATOBILIARY DISORDERS................................................... 42

6.10

IMMUNE SYSTEM DISORDERS.................................................. 43

6.11

INFECTIONS AND INFESTATIONS ............................................ 45

6.12

INJURY, POISONING AND PROCEDURAL COMPLICATIONS . 47

6.13

INVESTIGATIONS ........................................................................ 50

6.14

METABOLISM AND NUTRITION DISORDERS........................... 55

6.15

MUSCULOSKELETAL AND CONNECTIVE TISSUEDISORDERS ................................................................................ 56

6.16

NEOPLASMS BENIGN, MALIGNANT AND UNSPECIFIED (INCL
CYSTS AND POLYPS) ................................................................. 57

6.17

NERVOUS SYSTEM DISORDERS .............................................. 59

6.18

PREGNANCY, PUERPERIUM AND PERINATAL CONDITIONS 60

6.19

PRODUCT ISSUES ...................................................................... 62

6.20

PSYCHIATRIC DISORDERS........................................................ 64

6.21

RENAL AND URINARY DISORDERS ......................................... 66

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6.22

REPRODUCTIVE SYSTEM AND BREAST DISORDERS ........... 67

6.23

RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS 68

6.24

SKIN AND SUBCUTANEOUS TISSUE DISORDERS ................. 70

6.25

SOCIAL CIRCUMSTANCES ........................................................ 71

6.26

SURGICAL AND MEDICAL PROCEDURES ............................... 73

6.27

VASCULAR DISORDERS ............................................................ 75

APPENDIX A: ACRONYMS ........................................................................................ 76
APPENDIX B: MedDRA CONCEPT DESCRIPTIONS ................................................ 79

LIST OF TABLES
Table 3-1. The MedDRA Terminology SOC List – Alphabetical Listing ............. 18
Table 3-2. The MedDRA Terminology SOC List – Internationally Agreed
Order ............................................................................................... 19
Table 6-1. Sample of Exceptions and Conventions in SOC Immune System
Disorders ......................................................................................... 43

LIST OF FIGURES
Figure 2-1. Structural Hierarchy of the MedDRA Terminology .......................... 12

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1. INTRODUCTION
The Medical Dictionary for Regulatory Activities (MedDRA) Terminology is theinternational medical terminology developed under the auspices of the International
Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human
Use (ICH). This guide describes the development, scope, and structure of theterminology.
1.1

BACKGROUND

Prior to the development of MedDRA, there had been no internationally accepted
medical terminology for biopharmaceutical regulatory purposes. Most organizations
processing regulatory data used one of the international adverse drug reaction
terminologies in combination with morbidity terminology. In Europe, most of theseorganizations used a combination of the World Health Organization's Adverse Reaction
Terminology (WHO-ART) and the International Classification of Diseases Ninth
Revision (ICD-9). In the United States, the Food and Drug Administration's (FDA)
Coding Symbols for a Thesaurus of Adverse Reaction Terms (COSTART) was usuallyused in conjunction with Clinical Modification of ICD-9 (ICD-9-CM). The Japanesedeveloped their own versions of these international terminologies, Japanese Adverse
Reaction Terminology (J-ART) and Medical Information System (Japan) (MEDIS). In
addition, many organizations modified these terminologies to suit their needs.
Established terminologies lacked specificity of terms at the data entry level, provided
limited data retrieval options (e.g., too few levels in the hierarchy, or capacity to retrieve
data via one axis only), and did not handle syndromes effectively. Organizations with
sufficient resources developed their own “in-house” terminologies to address some or allof these deficiencies.
The use of multiple terminologies raised several problems. Using different
terminologies at various stages in a product's life complicates data retrieval andanalysis, making it difficult to cross-reference data. For example, safety data had
frequently been classified for pre-registration clinical trials using ICD terminology and forpost-marketing surveillance using J-ART, WHO-ART, or COSTART. Furthermore,using different terminologies in separate geographic regions impaired international
communication and necessitated the conversion of data from one terminology toanother. This data conversion had the potential to cause time delays and loss or
distortion of data. In particular, these problems affected multinational pharmaceuticalcompanies whose subsidiaries used multiple terminologies to fulfill the different datasubmission requirements of regulators. The use of multiple terminologies also affected
communication between companies and clinical research organizations.
It became increasingly difficult to manage the information required for productregistration applications and to meet the time scale requirements for data exchange
between regulatory authorities and the medical product industries. These difficulties
prompted an industry-wide commitment to exploit developments in communication andinformation technology. However, electronic communication still required astandardized data set and structure to be successful.
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1.2 ADOPTION OF MEDICAL TERMINOLOGY AS AN ICH TOPICIn October 1994, the ICH Steering Committee introduced multi-disciplinary regulatorycommunication initiatives to complement the ongoing safety, quality, and efficacy
harmonization topics. These initiatives focused on a medical terminology for regulatory
purposes (M1) and electronic standards for the transfer of regulatory information(ESTRI, M2). The ICH adopted these initiatives to recognize the increasing importanceof electronic communication of regulatory data and the need for internationally agreed
standards.
The aim of the ICH M1 initiative was to standardize the international medical
terminology for regulatory communication. This includes communication in theregistration, documentation, and safety monitoring of medical products for use in bothpre- and post-marketing phases of the regulatory process. The objective was to agree
on a unified medical terminology for regulatory activities that overcomes the limitationsof current terminologies, is internationally accepted, and is supported by long-term
maintenance. Regulators and industries benefit from such a terminology because it
improves the quality, timeliness, and availability of data for analysis. The terminology
also facilitates the electronic exchange of data relating to medical products and resultsin long-term savings in resources.
The M1 Expert Working Group (EWG) was established and was composed ofrepresentatives of the six ICH sponsors, an observer for the WHO, and the European
Union acting as rapporteur. The EWG defined the “deliverables” of the initiative as aterminology of agreed content and structure (the implementable version) and an agreed
maintenance framework.
1.3

DEVELOPMENT OF THE MEDICAL DICTIONARY FOR REGULATORYACTIVITIES (MedDRA) TERMINOLOGYThe ICH terminology was developed from a pre-existing terminology. The MEDDRAWorking Party enhanced the United Kingdom MCA's(now MHRA - Medicines and
Healthcare products Regulatory Agency) medical terminology to produce MEDDRA
Version 1.0. This was adopted as the basis for the new ICH terminology.
MedDRA Version 2.0 was signed off as the implementable version of the terminology at
the ICH-4 conference in July 1997. A change in name and modified acronym wereagreed upon at this meeting. Hence, MEDDRA is used for versions up to Version 1.5,
while the implementable version (Version 2.0) and future versions are known as the
MedDRA terminology.
1.4

IMPLEMENTATION OF THE TERMINOLOGY

The success of the terminology depends on its long-term maintenance and its evolution
in response to medical/scientific advances and changes in the regulatory environment.
This is why the MedDRA Maintenance and Support Services Organization (MSSO) is a
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necessary element to implementing the MedDRA terminology. The MSSO wasappointed by ICH through an open competitive tender.
1.5

SCOPE OF THE TERMINOLOGY

The MedDRA terminology applies to all phases of development of medical products forhuman use, excluding animal toxicology. The scope of MedDRA encompasses medical,
health-related, and regulatory concepts pertaining to such products. The terminology
also addresses the health effects and malfunction of devices (e.g., PT Device related
infection and PT Device failure). Furthermore, the terminology may also support othertypes of products which are regulated in at least one region such as food or cosmetics.
The categories of terms classified as “medical and health-related” for these purposes
are as follows:










signs
symptoms
diseasesdiagnoses
therapeutic indications – including signs, symptoms, diseases, diagnoses,
diagnosis or prophylaxis of disease, and modification of physiologic function
names and qualitative results of investigations – e.g., increased, decreased,
normal, abnormal, present, absent, positive, and negative
medication errors and product quality terms
surgical and medical procedures
medical/social/family history

Although social circumstances are not usually regarded as medical terms, they fallwithin the “medical” scope if they are relevant to the evaluation of regulatory data (e.g.,in the assessment of clinical outcome of treatment in the light of exposure to risk
factors). Examples are: PT Foreign travel, PT Substance use, HLT Tobacco use, andHLT Bereavement issues. The terminology, as defined above, was developed forregulators and the regulated medical product industry. These groups can utilize theterminology for data entry, retrieval, evaluation, and presentation, and in both pre- andpost-marketing phases of the regulatory process as follows:clinical studies
reports of spontaneous adverse reactions and events
regulatory submissions
regulated product information

In consultation with the MedDRA Management Committee, the terminology may be
expanded in scope to accommodate additional medical/health-related and regulatory
concepts that are developed based on collaborative efforts involving relevant experts.
The addition of new topic areas will undergo the usual MSSO change request process.

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1.6 INCLUSION OF TERMS FROM ESTABLISHED TERMINOLOGIESThe initial release of MedDRA (v2.1) in March 1999 included numeric and symbol codesfrom earlier terminologies in specific fields of the MedDRA files associated with termnames. The codes were links from other terminologies to similar or identical terms in
MedDRA and included codes from COSTART (5th Edition), WHO-ART© (3rd Quarter,
1998), ICD9, ICD9-CM, HARTS© (Release 2.2), and J-ART (1996). For example, PT
Nausea in MedDRA has a corresponding term NAUSEA in COSTART.
MedDRA was not developed as a metathesaurus, and the hierarchies of these otherterminologies are not subsets of it. Thus, data entry terms from other terminologies do
not necessarily have the same PT in MedDRA as they did in their “parent” terminology.
The hierarchies used for data retrieval and presentation are unique to MedDRA.
Inclusion of terms from other terminologies is restricted to those within the scope of
MedDRA as defined above.
The ICH M1 Expert Working Group – who created the original version of MedDRA –included the numeric and symbol codes with the text of the terms; the codes wereintended to be useful in the transition to MedDRA. Since most organizations have
converted their data from older terminologies to MedDRA, and the codes have not been
maintained or updated since the original release of MedDRA, the MSSO has removed
them from the MedDRA files as of MedDRA v15.0.
Note that no MedDRA term names or codes have been modified or removed as a resultof this action, and the structure of the MedDRA extended ASCII files has not changed.
1.7

EXCLUSION CRITERIAThe exclusion criteria used in the development of the terminology do not necessarily
limit the terminology's expansion scope. Since this is a medical terminology, thefollowing terms used in regulatory affairs are out of scope:Drug/product terminology (Note: The generic names of some commonly usedproducts, such as digoxin, that are included with their associated adverse events)



Equipment/device/diagnostic product terminology

Study design

Demographics (including patient sex, age, race, and religion).

As its focus is on health effects in individual patients, the following are excluded:
Qualifiers that refer to populations rather than individual patients (e.g., rare,frequent)

Numerical values associated with laboratory parameters are not included (e.g.,serum sodium 141 mEq/L). See Section 4.9 for more details.

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2. STRUCTURAL ELEMENTS OF THE TERMINOLOGY
The MedDRA terminology was developed as a medically validated medical terminology
for utilization throughout the regulatory process. The developers of the terminology
designed a structure that promotes specific and comprehensive data entry and flexible
data retrieval. Figure 2-1 represents the hierarchical structure of the terminology.
Relationships between terms in the terminology fall into the following two categories:
2.1

EQUIVALENCEThe equivalence relationship groups synonymous terms, or equivalent terms, underPreferred Terms.
2.2

HIERARCHICAL

The hierarchy provides degrees or levels of superordination and subordination. The
superordinate term is a broad grouping term applicable to each subordinate descriptor
linked to it. Hierarchical levels thus represent vertical links in the terminology.
Hierarchies are an important mechanism for flexible data retrieval and for the clear
presentation of data. The five-level structure of this terminology provides options for
retrieving data by specific or broad groupings, according to the level of specificity
required. The Lowest Level Term (LLT) level provides maximum specificity.
The terminology was not developed as a formal classification or taxonomy; each level inthe hierarchy may reflect a variable degree of specificity or “granularity” from one
System Organ Class to another. High Level Terms (HLTs) and High Level Group Terms(HLGTs) facilitate data retrieval and presentation by providing clinically relevantgrouping of terms. Collectively, the HLT and HLGT levels are sometimes referred to as
the “grouping terms” in MedDRA.
The 27 System Organ Classes (SOCs) represent parallel axes that are not mutually
exclusive. This characteristic, called “multi-axiality,” allows a term to be represented in
more than one SOC and to be grouped by different classifications (e.g., by etiology or
manifestation site), allowing retrieval and presentation via different data sets. Groupingterms are pre-defined in the terminology and not selected on an ad hoc basis by data
entry staff. Rather, the terminology is structured so that selection of a data entry term
leads to automatic assignment of grouping terms higher in the hierarchy. Multi-axial
links of terms are pre-assigned in MedDRA, ensuring comprehensive and consistent
data retrieval, irrespective of which SOC is selected at data retrieval.

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Structural Elements of the Terminology

System OrganClass (SOC)High Level Group
Term (HLGT)High Level Term
(HLT)

Preferred Term
(PT)

Lowest Level Term
(LLT)

Figure 2-1. Structural Hierarchy of the MedDRA Terminology

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3. LEVELS OF STRUCTURAL HIERARCHY
The levels of structural hierarchy are characterized as follows:
3.1

LOWEST LEVEL TERMS

LLTs constitute the lowest level of the terminology. Each LLT is linked to only one PT.
LLTs have any of the following relationships to their parent PT:
Synonyms: Different terms for the same concept inherent in the PT (e.g., PT
Arthritis and its subordinate LLT Joint inflammation)
Lexical variants: Different word forms for the same expression. These include
full names vs. abbreviations and direct vs. inverted word order (e.g., PT
Acquired immunodeficiency syndrome and its subordinate LLT AIDS or PT
Biopsy tongue and its subordinate LLT Tongue biopsy).
Quasi-synonyms: Quasi-synonyms are terms that are not precisely the same
meaning as another term, but are treated as synonymous in a given
terminology. These include site and laterality descriptions (e.g., PT Otitis
externa and its subordinate LLT Bilateral otitis externa).
Sub-concept: Sub-concepts (of the parent PT concept) are represented by LLTs
with more detailed information such as anatomic specificity (e.g., PT
Contusion with LLT Bruising of face or LLT Bruising of leg).
Identical LLT: One LLT is identical to its PT for data entry purposes (e.g., PT
Dementia Alzheimer's type and its subordinate LLT Dementia Alzheimer'stype). In this instance, the LLT and parent PT have the same MedDRA code
but appear at both levels.
Since LLTs may accommodate colloquial or culturally unique terms, every LLT may nothave a unique translation in every language.
The LLT level plays an important role in facilitating the transfer of historical data
because many of the terms from other terminologies incorporated, are represented at
this level.
LLTs facilitate data entry and promote consistency by decreasing subjective choices
made at this stage. LLTs may also be used as the basis for auto-encoding. Since LLTs
may be more specific than the PT to which they are linked, users can retrieve data at
the most specific level of the terminology.
LLTs carry a “current” or “non-current” flag status. Terms that are very vague,
ambiguous, truncated, abbreviated, out-dated, or misspelled carry a non-current flag.
These terms may derive from terminologies incorporated into MedDRA. The
terminology retains LLTs with a non-current flag to preserve historical data for retrieval
and analysis. The flag also allows users to implement the terminology within a
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Levels of Structural Hierarchy

database and prevent the inadvertent use of non-current LLTs in post-implementation
coding.
3.2

PREFERRED TERMS

A PT is a distinct descriptor (single medical concept) for a symptom, sign, disease,diagnosis, therapeutic indication, investigation, surgical, or medical procedure, andmedical, social, or family history characteristic.
PTs should be unambiguous and as specific and self-descriptive as possible in thecontext of international requirements. Therefore, eponymous terms are only used when
they are recognized internationally.
The granularity/specificity of the PT level is such that clinical pathologic or etiologic
qualifiers of the descriptors are represented at the PT level. For example, a variety ofrhinitis and meningitis terms exist as separate entities at this level (e.g., PT Rhinitis
perennial, PT Rhinitis ulcerative, PT Rhinitis atrophic, PT Meningitis aseptic, PT
Meningitis cryptococcal, PT Meningitis viral, PT Meningitis bacterial, etc.). This level of
specificity in PTs ensures that the multi-axial nature of the terminology can be
maximally exploited.
There is no limit to the number of LLTs that can be linked to a PT, however, a PT musthave at least one LLT linked to it. When a new PT is added to the terminology, an
identical LLT is created automatically for data entry purposes.
PTs are subordinate to HLTs.
A PT must be linked to at least one SOC. A PT can be linked to as many SOCs as isappropriate. It can only be linked to each SOC via one HLT=>HLGT=>SOC route. EachPT has a primary SOC that determines under which SOC the term appears incumulative data outputs.
3.3

HIGH LEVEL TERMSAn HLT is a superordinate descriptor for the PTs linked to it. It is an inclusive category
which links PTs related to it by anatomy, pathology, physiology, etiology, or function.
Examples of HLTs are: HLT Bronchospasm and obstruction, HLT Mediastinal
disorders, HLT Pulmonary oedemas, and HLT Upper respiratory tract neoplasms.
The terminology is not a taxonomy, so the specificity of HLTs is not uniform throughout
the terminology (or between SOCs).
HLTs are intended for data retrieval and presentation purposes; they are a groupinglevel and are not intended to be a coding level.
HLTs are subordinate to HLGTs. An HLT must be linked to at least one SOC via an
HLGT. It can only be linked to a particular SOC via one route (i.e., linked to only one
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Levels of Structural Hierarchy

HLGT per SOC). All HLTs linked to a particular HLGT will appear in every SOC towhich the HLGT is linked.
3.4 HIGH LEVEL GROUP TERMSAn HLGT is a superordinate descriptor for one or more HLTs related by anatomy,
pathology, physiology, etiology, or function. For example, HLGT Vascular hypertensive
disorders is used to link the following HLTs: HLT Accelerated and malignant
hypertension, HLT Hypertension complications, HLT Portal hypertensions, HLT
Pregnancy associated hypertension, HLT Pulmonary hypertensions, HLT Renal
hypertensions, HLT Vascular hypertensive disorders NEC, and HLT Endocrine andmetabolic secondary hypertension.
HLGTs are intended for data retrieval and presentation purposes. HLGTs group HLTs
to aid retrieval by broader concepts.
HLGTs are subordinate to SOCs. An HLGT must be linked to at least one SOC and toat least one HLT (the next levels up and down in the hierarchy, respectively).
There is no limit to the number of SOCs to which an HLGT can be linked.
3.5

SYSTEM ORGAN CLASSA SOC is the highest level of the hierarchy that provides the broadest concept for data
retrieval. SOCs comprise groupings by:

Etiology (e.g., SOC Infections and infestations)

Manifestation site (e.g., SOC Gastrointestinal disorders)

Purpose (e.g., SOC Surgical and medical procedures)

The exception from the above categories is SOC Social circumstances which contains
information about the person, not the adverse event and provides a grouping for thosefactors that may give insight into personal issues that could have an effect on the event
being reported.
A SOC is related directly (superordinated) to at least one HLGT with no restriction on
the number of links to HLGTs.
To avoid “double counting” while retrieving information from all SOCs, each PT is
assigned a primary SOC. This is required because PTs can be represented in morethan one SOC (multi-axiality). It prevents an individual PT from being displayed morethan once in cumulative SOC-by-SOC data outputs, which would result in over-countingof terms. All PTs in MedDRA are assigned a primary SOC that determines the SOC in
which the term is displayed in these outputs. This property does not prevent display
and counting of the term in any of the SOCs in which it is represented for data retrieval
purposes that do not involve all SOCs.
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The following rules are used for the allocation of the primary SOC: PTs that are only represented in one SOC are automatically assigned that SOC
as primary.


PTs relating to diseases or signs and symptoms are assigned to the prime
manifestation site SOC with the following exceptions:Terms for congenital and hereditary anomalies are assigned to SOC
Congenital, familial and genetic disorders as the primary SOC.
Terms for neoplasms are assigned to SOC Neoplasms benign, malignant
and unspecified (incl cysts and polyps) as primary SOC. This does not
apply to cyst and polyp terms. These terms have as their primary SOC
the manifestation site SOC. For example, PT Aural polyp has SOC Ear
and labyrinth disorders as its primary SOC and SOC Neoplasms benign,malignant and unspecified (incl cysts and polyps) as its secondary SOC.
Terms for infections are assigned to SOC Infections and infestations as
the primary SOC.

If a PT links to more than one of these three “exceptions” SOCs, the following priority isused to determine the primary SOC:

SOC Congenital, familial and genetic disorders
SOC Neoplasms benign, malignant and unspecified (incl cysts and polyps)



SOC Infections and infestations.

As an example, PT Congenital teratoma is linked to SOC Congenital, familial andgenetic disorders as the primary SOC with a secondary link to SOC Neoplasms benign,malignant and unspecified (incl cysts and polyps).
The decision was made during the development of MedDRA to abrogate the generalrule of manifestation site (rather than etiology) when determining the primary SOC
allocation for neoplasms, congenital abnormalities, and infections. This was done tofacilitate signal identification, since all PTs relating to such categories are grouped
together on routine cumulative data outputs.
Other considerations for primary SOC allocation are as follows:

Not all SOCs in MedDRA express multi-axiality. Terms contained within SOC
Investigations, SOC Social circumstances, and SOC Surgical and medical
procedures reside within those SOCs and nowhere else in the terminology
because they lack multi-axial linkages.



The majority (but not all) of injury, poisoning and procedural complications terms
are represented in SOC Injury, poisoning and procedural complications as theprimary SOC.

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General disorders and administration site conditions, while infections at thesesites have the primary SOC Infections and infestations.

The Alphabetical Listing of MedDRA SOCs is presented in Table 3-1 (in English).
Presented in Table 3-2 are the MedDRA SOCs listed in the internationally agreed order.
The original MedDRA Expert Working Group determined there is not a standard
alphabetic order of SOCs due to the multi-lingual nature of MedDRA. As a result, they
developed the international order to facilitate consistency irrespective of language oralphabet.
SOC Blood and lymphatic system disorders
SOC Cardiac disorders
SOC Congenital, familial and genetic disorders
SOC Ear and labyrinth disorders
SOC Endocrine disorders
SOC Eye disorders
SOC Gastrointestinal disorders
SOC General disorders and administration site conditions
SOC Hepatobiliary disorders
SOC Immune system disorders
SOC Infections and infestations
SOC Injury, poisoning and procedural complications
SOC Investigations
SOC Metabolism and nutrition disorders
SOC Musculoskeletal and connective tissue disorders
SOC Neoplasms benign, malignant and unspecified (incl cysts andpolyps)SOC Nervous system disorders
SOC Pregnancy, puerperium and perinatal conditions
SOC Product issues
SOC Psychiatric disorders
SOC Renal and urinary disorders
SOC Reproductive system and breast disorders
SOC Respiratory, thoracic and mediastinal disorders
SOC Skin and subcutaneous tissue disorders
SOC Social circumstances
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SOC Surgical and medical procedures
SOC Vascular disorders
Table 3-1. The MedDRA Terminology SOC List – Alphabetical Listing

SOC Infections and infestations
SOC Neoplasms benign, malignant and unspecified (incl cysts andpolyps)SOC Blood and lymphatic system disorders
SOC Immune system disorders
SOC Endocrine disorders
SOC Metabolism and nutrition disorders
SOC Psychiatric disorders
SOC Nervous system disorders
SOC Eye disorders
SOC Ear and labyrinth disorders
SOC Cardiac disorders
SOC Vascular disorders
SOC Respiratory, thoracic and mediastinal disorders
SOC Gastrointestinal disorders
SOC Hepatobiliary disorders
SOC Skin and subcutaneous tissue disorders
SOC Musculoskeletal and connective tissue disorders
SOC Renal and urinary disorders
SOC Pregnancy, puerperium and perinatal conditions
SOC Reproductive system and breast disorders
SOC Congenital, familial and genetic disorders
SOC General disorders and administration site conditions
SOC Investigations
SOC Injury, poisoning and procedural complications
SOC Surgical and medical procedures
SOC Social circumstances
SOC Product issues
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Table 3-2. The MedDRA Terminology SOC List – Internationally Agreed Order
3.6

STANDARDISED MedDRA QUERY (SMQ)

Standardised MedDRA Queries (SMQs) are groupings of MedDRA terms, ordinarily at
the Preferred Term (PT) level that relate to a defined medical condition or area ofinterest. SMQs are intended to aid in the identification and retrieval of potentiallyrelevant individual case safety reports. The included terms may relate to signs,
symptoms, diagnoses, syndromes, physical findings, laboratory and other physiologic
test data, etc. The only Lowest Level Terms (LLTs) represented in an SMQ are thosethat link to a PT used in the SMQ; all others are excluded.
For detailed information about the SMQs, please refer to the Introductory Guide forStandardised MedDRA Queries (SMQs), which is a separate document. It can be foundalong with the other supporting user documentation with this release.

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4. RULES AND CONVENTIONS ADOPTED IN THE TERMINOLOGY(INCLUDING PRESENTATION AND FORMATTING OF TERMS)
This section, and sections 5 and 6 contain the rules and conventions used in theterminology. Each rule holds true in the majority of cases, but many rules will have
exceptions. Some of those exceptions are listed within each rule, however, it is notpossible to notate all exceptions. MedDRA is a medical terminology not a taxonomy
and medically must be balanced, pragmatic, reflect actual medical practice, and haveconsideration for how different cultures interpret specific terms.
4.1

SPELLING

Terminology spelling consistently follows Dorland's Illustrated Medical Dictionary (30thedition), Dorland's online and standard medical literature for all medical terms.
Nonmedical terms included in the terminology follow Merriam-Webster® English
Dictionary.
Use of the hyphen is consistent with its most prevalent use in Dorland's Illustrated
Medical Dictionary and standard medical literature. “Non” in a word will always be usedwith a hyphen unless it is a term not found in Dorland's but is accepted in the MerriamWebster English Dictionary as one word (e.g., nontoxic, nonspecific, noninvasive,
nondependent, nonmedical, nonproductive, noncompliance, nondominant, etc).
In accordance with Dorland's Illustrated Medical Dictionary, “post” terms are separated
by a space with the following exceptions: hyphenated terms include “post-traumatic,”“postero-lateral,” and “post-term.” Examples of single word terms include forms of“postabortal,” “postpartum,” “postmature,” “postmenopausal,” “postmastoid,”“postvaccinal,” “postvaccinial,” “postnasal,” “postauricular,” “postictal,”“postmastectomy,” and “postnatal.”
British spellings are used at the PT level and above. At the LLT level, both the British
spelling and the American spelling counterpart of the same term are included (e.g., LLT
Diarrhoea and LLT Diarrhea under PT Diarrhoea). Misspelled terms that come frominherited terminologies are flagged as non-current.
4.2

ABBREVIATIONS

In general, abbreviations are excluded from levels above LLT. Exceptions to this rule
are: 1) when including the full term makes the phrase very long (over 100 characters);
and 2) when the term has a well-established abbreviation. Below are some examples:
CDC Centers for Disease Control (USA)CNS central nervous system
CSF

cerebrospinal fluid

ECG electrocardiogram

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The following abbreviation is limited to the HLT and HLGT levels (with the exception ofa few non-current LLTs):
NEC not elsewhere classified
The following abbreviation is limited to the LLT level:
NOS not otherwise specified
Abbreviation letters are not punctuated by full stops (periods). Abbreviations oracronyms that may represent different meanings in the various ICH regions are
excluded from the terminology to prevent ambiguity. Abbreviations and acronyms
exhibiting multiple interpretations in standard text books of acronyms are generally notaccepted for addition into the terminology. However, an acronym will be added, despite
multiple interpretations, at the LLT level for its most common usage worldwide e.g.,LLT
CVA for Cerebrovascular accident and LLT Raised LFTs for Raised liver function tests.
Based upon advice from the MedDRA Expert Panel, the majority of abbreviated virus
LLTs (and related terms without abbreviations and a qualifier), which can be interpreted
as either an investigation or infection terms such as LLT HAV, LLT HBV, and LLTHepatitis B virus, are non-current. As of MedDRA 12.1, the MSSO will refrain fromadding new abbreviated terms without the qualifier of “test” or “infection.”
The chemical elements are represented in MedDRA with their official chemical symbols
on LLT level such as “Cl” for chloride and “Cu” for copper.
4.3

CAPITALIZATION

Most of the terminology is presented in lower case letters. Upper case letters are used
only for the initial letter in each term, with the exception of proper names (e.g., PT NonHodgkin's lymphoma), and components of microorganism taxonomic names andabbreviations.
Terminologies, dictionaries, and thesauri traditionally use a mixture of lower and upper
case letters to indicate the correct orthography of terms. However, organizations havecomplete flexibility regarding how they implement term case in their databases. Upper
case terms can be used exclusively if desired.
4.4

PUNCTUATIONApostrophes are used in proper names (e.g., PT Gilbert's syndrome).
Diacritical marks, for example the French “accent aigu” or “é,” (e.g., PT Guillain-Barre
syndrome) are excluded from the English version of the terminology.
4.5

SINGLE WORD VS. MULTIPLE WORD TERMS

Each LLT or PT represents a single concept, but the concept may be expressed in one
or more words.
Terms describing two or more concepts were “inherited” from other terminologies (e.g.,
LLT Nausea vomiting and diarrhoea). These compound terms are linked as LLTs to the
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PT that denotes the primary or most clinically relevant effect. For example, the term
LLT Nausea vomiting and diarrhoea is linked to PT Vomiting. Additionally, this term has
been flagged non-current.
4.6 WORD ORDER
In general, the PT, HLT, HLGT, and SOC levels use natural language word order whichmeans the term is expressed in the way it is generally spoken (e.g., PT Myocardial
infarction, not “Infarction myocardial”). The exception is when reversing the words in a
PT facilitates grouping of similar terms for alphabetical display in SOC hierarchies. For
example: PT Meningitis aseptic, PT Meningitis chemical, PT Meningitis eosinophilic,and PT Meningitis toxoplasmal.
4.7

MedDRA CODES

In contrast to the typical use of the word “code” in the regulatory milieu, within MedDRA,
the “code” refers to the eight-digit number assigned to each term and is not to be
confused with the text string of the term itself. Each term in MedDRA has a unique nonexpressive code. Non-expressive, in this context, means that no information can bederived from the digits within the code (e.g., SOC assigned level within the hierarchy,etc.). A code is assigned to all terms across all categories. Initially, the codes wereassigned in alphabetical order starting with 10000001. New terms added to theterminology are assigned the next sequential number. Previously used MedDRA codes
are usually not reused for new terms, however, in some circumstances, when terms arerenamed (e.g., the correction of misspellings), codes may be reused.
4.8

BODY SITE CONSIDERATIONS IN MedDRA

Abdominal wall – In general, the abdominal wall is classified in MedDRA as agastrointestinal structure. There is not a formal definition for abdominal wall in MedDRA
but, for the purpose of term placement, the MSSO considers the abdominal wall tocomprise the peritoneum, muscles and fascia enclosing the abdominal cavity, thusclassifying it as a gastrointestinal structure. The umbilicus and periumbilical area areconsidered to be skin structures and therefore are linked to SOC Skin andsubcutaneous tissue disorders.
Cardiac and vascular anomalies – Certain congenital anomalies include both cardiac
and vascular components; these terms are linked to HLT Congenital cardiovasculardisorders NEC (with HLGT Congenital cardiac disorders linking it to SOC Cardiac
disorders).
Chest wall - The chest wall is classified as a musculoskeletal structure. In general,terms related to the chest wall are linked to SOC Musculoskeletal and connective tissue
disorders.

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Eyelid - The eyelid is classified as a structure of the eye. In general, terms related tothe eyelid are primarily linked to SOC Eye disorders and secondarily to SOC Skin andsubcutaneous tissue disorders.
Pharynx and diaphragm - The pharynx and diaphragm are classified in MedDRA as
respiratory structures.
Pinna - The pinna, including the ear lobe, is considered part of the ear and has a
primary link to SOC Ear and labyrinth disorders.
4.9 NUMERICAL VALUES
Some MedDRA LLTs contain numerical values associated with certain clinicalparameters (e.g., LLT Foetal growth retardation, unspecified, 1,500-1,749 grams);
usually these are terms incorporated from other terminologies, and are flagged noncurrent since they do not fit MedDRA rules. Numerical values associated withlaboratory parameters are also excluded (e.g., serum sodium 141 mEq/L).
Numerals may be incorporated into LLTs and PTs when they are part of a name orinherent to the concept (e.g., PT 5-alpha-reductase deficiency).
4.10 AGGRAVATION OF UNDERLYING CONDITIONS
The majority of terms expressing “aggravated” concepts (e.g., LLT Allergy aggravated)have been inherited from other terminologies. As a result of the modified term review,
several similar concepts were added in MedDRA Version 9.1. However, in the future
the MSSO will add new terms containing “aggravated,” “worsen/-ed/-ing,” or“exacerbated,” only if they demonstrate medical significance.
4.11 NOS AND NEC TERMS
Terms including “NOS” (not otherwise specified) are a common feature of medical
terminologies used within drug regulatory affairs. In MedDRA, “NOS” terms are only
found on the LLT level and are meant to represent concepts for which no further specificinformation is available (e.g., during coding of adverse events). Terms carrying “NOS”
reflect nonspecific terms and can only be interpreted with reference to other terms
specified in the terminology. The specified concept is not a constant throughout thisterminology (e.g., it may relate to acute vs. chronic conditions, body site, or infective
organism). For coding, users should employ the most specific term available (e.g., LLT
Cluster headaches vs. LLT Headache NOS). At the direction of the MedDRAManagement Committee, as of MedDRA Version 6.1, no additional “NOS” terms will be
accepted into the terminology. Additionally, all “NOS” terms previously existing at the
PT level have been demoted to the LLT level in the terminology.
Similarly, “NEC” (not elsewhere classified) is a standard abbreviation used to denotegroupings of miscellaneous terms that do not readily fit into other hierarchicalclassifications within a particular SOC. The “NEC” designation is used only with HLTs
and HLGTs for grouping purposes. For example, HLT Bladder disorders NEC includes
a diverse range of PTs including PT Bladder stenosis, PT Bladder granuloma and PT
Bladder telangiectasia. All “NEC” terms previously existing at the PT level have been
demoted to the LLT level and flagged non-current.
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4.12 GENDER SPECIFIC TERMS
In general, gender specific terms are not included in MedDRA because patient gender
is traditionally considered a database variable. However, a special case has been
made for instances in which the gender of the patient makes the concept clinicallydistinct as for certain breast and reproductive tract disorders (e.g., PT Breast cancer
male and PT Breast cancer female). In general, there is also a corresponding genderneutral term (PT Breast cancer).
4.13 HIERARCHY NAMING CONVENTIONSPlurality
Terms at the HLT and HLGT levels are normally in the plural form since they aregroupings of medical concepts (e.g., HLT Malignant hepatobiliary neoplasms).
Generally, terms at the PT and LLT levels are in the singular form since they are notgroupings of medical concepts.
Use of Adjectives
The adjective form, e.g., “cardiac” or “hepatic” is used whenever possible instead of thenoun (e.g., “heart” or “liver”). The exceptions are when there is a naming conflict (i.e.,
two terms at different levels that could potentially be represented by the same text
string) or when the term is not normally stated as such in common practice. For
example, “heart attack” is normally used in common practice rather than “cardiac
attack.”“Excl” and “Incl”
In order to be consistent with the conventions for the grouping terms, the standard useof terms with “including” or “excluding” are represented as the following:
1. “excl” represents excluding, “except,” and “excl.”
2. “incl” represents including and “incl.”“Signs and symptoms;” “infections and inflammations”
In the text of terms where such phrases are used, the word order is “signs andsymptoms” and “infections and inflammations.”
Benign and malignant
Generally, words “benign” and “malignant” are placed at the end of the text strings in
SOC Neoplasms benign, malignant and unspecified (incl cysts and polyps) and at the
beginning of the text strings in other SOCs. This convention provides information as towhich SOC and HLGT the term belongs to by reading its name only.
Congenital
Generally, the word “congenital” is placed at the end of the text string in SOC
Congenital, familial and genetic disorders and at the beginning of the term in other
SOCs. This convention provides information as to which SOC and HLGT the term
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belongs by only reading its text string. The term “congenital” has been used to describe
any condition present at birth, whether genetically inherited or occurring in utero.
Disorder, disease, and disturbanceIn MedDRA, the concept of “disturbance” is subordinate to “disease” which issubordinate to “disorder.” “Disorder” is generally used in the HLT, HLGT, and SOC
levels since it is more of a general term (e.g., HLGT Gallbladder disorders). As an
exception, “disease” is sometimes used at the HLT level when this is the most common
way of stating the concept e.g., HLT Parkinson's disease and parkinsonism.
“Parkinson's disease” is the most common way of stating the term, not “Parkinson's
disorder.”“Disturbance” is synonymous with “disorder” and will be only added if that is thepreferred wording for a concept. If a “disorder” term exists at the PT/LLT level, the“disturbance” concept will no longer be added.

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5. PT AND LLT NAMING CONVENTIONS
5.1

GENERAL WORD USAGE

Alcohols: Single word names are used for alcohols (e.g., “ethanol,” not “ethyl
alcohol”). The symbol –OH is spelled out (e.g., LLT 17-hydroxycorticosteroid activity).
Anastomosis: This is classified as a surgical procedure and is single-axial linked to
SOC Surgical and medical procedures. Alternative terms are used to describe relateddisorders outside of the surgical realm.
Cervical (neck) and Cervix (uterus): In general, the word “cervical” is used to identify
the neck location whereas “cervix” is used to identify the uterine location. When a“cervical” term refers to the uterus, it carries the qualifier of “uterine” to differentiate itfrom cervical spine conditions. Exceptions to this latter convention are concepts that
could only relate to the uterine location (e.g., PT Cervical dysplasia) and thus require nofurther qualification.
Dilation and Dilatation: Standard medical definitions of “dilation” and “dilatation”
indicate that they are synonyms. The MSSO recognizes that there are some common
usages in certain cultures for these types of terms. However, for purposes of distinctionin MedDRA, the term “dilation” is considered a procedure and the term “dilatation” isconsidered a disorder. The word “procedure” is normally added to “dilation,” e.g., PT
Stomach dilation procedure to make it self-explanatory. An exception to this convention
is PT Uterine dilation and curettage, since it is recognized as a procedure without theaddition of the qualifying word.
Drainage (surgical/procedural term) and Discharge (non-surgical secretion term):“Drainage” is a term used as a procedure (systematic withdrawal of fluids), whereas“discharge” and “secretion” are terms used for the excretion of liquids from the body.
“Drainage” terms that fall outside of the realm of surgical procedures are considered
exceptions and dealt with by using the word “discharge.” These terms are linked
appropriately based on their particular meaning (e.g., PT Post procedural discharge
links to SOC Injury, poisoning and procedural complications). In addition, all surgicalterms retain “drainage” and link to SOC Surgical and medical procedures. Finally, if aterm can be either a surgical procedure or a non-surgical term, then both the“term+drainage” (PT Post procedural drainage linked to SOC Surgical and medical
procedures) and the “term+discharge” (PT Post procedural discharge linked to SOC
Injury, poisoning and procedural complications) are present in the terminology andlinked as indicated above. The MSSO recognizes that there are some common usages
in certain cultures for these types of terms that may not be reflected by this MedDRA
rule. Subscribers are advised to make clear which concept applies – surgical, nonsurgical, or both – when submitting Change Requests.
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Failure and Insufficiency: In MedDRA, for the major body systems of cardiac,
hepatic, pulmonary, and renal, the words “failure” and “insufficiency” are usedsynonymously. In SOC Cardiac disorders, SOC Hepatobiliary disorders, SOC Renal
and urinary disorders, and SOC Respiratory, thoracic and mediastinal disorders, the“failure” term is generally at the PT level and the “insufficiency” term is at the LLT level(e.g., PT Cardiac failure and LLT Cardiac insufficiency).
Interpretations of the words “failure” and “insufficiency” can be problematic; some users
may interpret the concepts as synonymous while others interpret them as similar, butdiffering in severity (with “insufficiency” being less severe than “failure”). In order toreconcile this, MSSO decided to make the terms essentially synonyms for the major
body systems as described above. The MSSO realizes this means that many
subscribers will have a different interpretation of these words than MedDRA's, but
MSSO found this was the most practical solution for consistency in the terminology.
Gangrene Terms: Terms with “gangrene” or “gangrenous” have a primary link to SOC
Infections and infestations, except those specifically representative of a noninfective
concept (e.g. PT Dry gangrene).
Drug Product Names: Generic drug names are used (e.g., “digoxin,” not “Lanoxin”)but only appear in MedDRA because they give further clarification to their parent PT(e.g., PT Toxicity to various agents) in the early days of the terminology.
Greek Letters: Greek letters are spelled out (“alpha,” not “;” “beta,” not “β”).
Eponymous Terms: Eponymous terms are only used if recognized internationally(e.g., LLT Paul Bunnell test linked to PT Mononucleosis heterophile test).
Lesion: Lesion terms may be considered for inclusion in MedDRA when the word“lesion” is part of a medical concept, e.g., PT Glomerulonephritis minimal lesion or awell-documented medical concept, e.g., LLT Brain lesion. However, the term will not be
added when adding a broad “lesion” term only adds an additional imprecise term toexisting “disorder” concepts, e.g., “renal lesion,” when one could use for coding theexisting LLT Renal disorder under PT Renal disorder.
Lump (non-neoplastic): For MedDRA terms, the word “lump” is not consideredneoplastic. Terms with “lump” are linked primarily to the SOC that represents the site ofmanifestation.
Mass (non-neoplastic): For MedDRA terms the word “mass” is not consideredneoplastic. Terms with “mass” are linked primarily to the SOC that represents the siteof manifestation. ”Mass” terms which have no inherent anatomic site (e.g., PT Mass)are linked as primary to SOC General disorders and administration site conditions.
Nodule: In general, new terms containing “nodule” are not added to MedDRA, except
when a nodule represents a full diagnostic expression, e.g. PT Milker’s nodules.
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Tumor (neoplastic): Terms containing the word “tumo(u)r” are considered neoplastic.
PTs that represent tumors are linked primarily to SOC Neoplasms benign, malignant
and unspecified (incl cysts and polyps). The secondary link is to the site ofmanifestation when identified. If malignancy is not specified in a tumor term, it is linked
to an HLT that contains the wording ” …malignancy unspecified.”
Congenital and Acquired: For conditions or diseases existing in both congenital andacquired forms, the following convention is applied: the more common form of thecondition/disease is represented at the PT level without adding a qualifier of either“congenital” or “acquired.” For example, hypothyroidism is more commonly acquired
than congenital; therefore, the unqualified term is at the PT level (PT Hypothyroidism).
The less common form of the condition or disease will also be at the PT level but with aqualifier added. Using again the example of hypothyroidism, the less common
congenital form has the qualifier “congenital” at the PT level (PT Congenital
hypothyroidism). The addition of qualified LLTs under the non qualified PT term islimited in MedDRA. The qualified LLTs will only be added in instances where thelikelihood of occurrence of congenital and acquired condition is close to being the same.
The alignment of existing affected terms along the lines described above (i.e., the“acquired,” “congenital,” and unqualified terms) has already been carried out in
MedDRA Version 8.0. The subscriber Change Request process will drive the remainderof alignments of possible term sets.
Polyp Terms: The existing unqualified polyp terms in MedDRA (e.g., PT Gastricpolyps) currently default to a benign classification within SOC Neoplasms benign,malignant and unspecified (incl cysts and polyps). Newly accepted polyp terms will notinclude a qualifier of “benign.” Polyps are secondarily linked to SOC Neoplasms
benign, malignant and unspecified (incl cysts and polyps) and primarily linked to theappropriate site of manifestation SOC. Polyp terms with the qualifier of “malignant” will
no longer be added to MedDRA. Instead, it is recommended that subscribers use
available “malignant neoplasm” terms for their coding needs.
Death: Death terms are in SOC General disorders and administration site conditions
and may have additional secondary links to related site or etiology SOCs. For example,
PT Death is only linked to SOC General disorders and administration site conditions,while PT Death neonatal is linked primarily to SOC General disorders andadministration site conditions and secondarily to SOC Pregnancy, puerperium andperinatal conditions.
Foetal and maternal death terms are linked primarily to SOC Pregnancy, puerperium
and perinatal conditions as they are considered a special population.
“Death of a relative” is considered a social issue, and terms will be found linked only to
SOC Social circumstances.
“Cell death” is considered an exception and is linked primarily to SOC Metabolism andnutrition disorders because it is an event on a cellular, not organism, level.

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Occlusion and obstruction: In general, whenever referring to blood vessels, stents,
shunts, and catheters, the word “occlusion” is used at the PT level (PT Hepatic artery
occlusion). The word “obstruction” is generally used in association with non-vascular
terms, such as the gastrointestinal tract or respiratory system (e.g., PT Large intestinal
obstruction and PT Tracheal obstruction).
Injury and damage: Injury and damage concepts were discussed by a MedDRA Expert
Panel which resulted in new guidelines for MedDRA. Based on this, injury and damage
terms in MedDRA are considered generally as synonymous. Injury or damage to amajor organ that has a low probability for a traumatic causality will be placed primary to
the site of manifestation, unless causality ”due to accident” is the more obvious or themost probable. In this case, the term will be linked primary to SOC Injury, poisoning
and procedural complications. Following this guidance some liver injury terms were realigned. PT Cholestatic liver injury, PT Mixed liver injury, and PT Liver injury are
considered non-traumatic and are primarily linked to SOC Hepatobiliary disorders while
PT Traumatic liver injury is primarily linked to SOC Injury, poisoning and procedural
complications.
Intestine and Intestinal: Terms with a combination of small/large andintestine/intestinal refer to the anatomical site and not the severity of concepts, e.g., PT
Small intestinal haemorrhage and PT Large intestine polyp refer to the site of
haemorrhage and polyp respectively and not the severity of the two events.
Spine and Spinal: For the purposes of MedDRA, spine and spinal terms are
considered synonymous with vertebral and spinal column concepts rather than with thespinal cord, unless "spinal" clearly represents a neurological concept such as PT Spinal
claudication.
Unapproved and Unlabelled: For the purposes of MedDRA, the words “unapproved”
and “unlabelled”/”unlabeled” are considered synonymous and refer to the use of
products in a manner that is not specified in the product information (label) that has
been approved by a regulatory authority. For example, the concepts of unapproved
indication and unlabelled indication are similar in the following terms: PT Unintentionaluse for unapproved indication and LLT Intentional use for unlabelled indication.
5.2

GENERAL SEARCH STRATEGIESSingle-axial SOC search: SOC Investigations, SOC Social circumstances, and SOC
Surgical and medical procedures are single-axial SOCs. The terms in these SOCs are
only represented in these SOCs, i.e., they do not have links to any other SOCs in
MedDRA. If a search of MedDRA-coded data is to include laboratory test results, social
issues, or therapeutic procedures, these individual SOCs should be represented in thequery. For example, increased blood glucose is associated with diabetes mellitus;
however, PT Diabetes mellitus is represented in SOC Metabolism and nutrition
disorders and SOC Endocrine disorders, whereas PT Blood glucose increased is
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represented only in SOC Investigations. (Please refer to Section 6 - System OrganClasses - for additional information.)
6. SYSTEM ORGAN CLASSES
Explanatory Notes
Explanatory notes are provided for each SOC and cover its structure and the basis forclassification (e.g., anatomic, pathologic, or etiologic). These notes provide guidanceon use of the terminology to ensure effective and comprehensive data retrieval.
The total number of unique terms at each level of the MedDRA hierarchy can be foundin the latest version of the MedDRA Distribution File Format Document

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6.1

BLOOD AND LYMPHATIC SYSTEM DISORDERS

6.1.1 Basis for Classification
The terms within this SOC are primarily divided pathologically at the HLGT level. At
the HLT level, terms are further subdivided by etiology and pathology wherever
possible. For example, HLGT Haemolyses and related conditions consists of HLTs
that group together hemolytic PTs with common etiology (e.g., HLT Anaemias
haemolytic immune). HLTs concerning spleen, lymphatic, and reticuloendothelial
system disorders are divided on an anatomic basis. Finally, HLTs concerning
hematologic neoplasms have been classified according to histologic criteria.
Some HLTs are meant to address a relevant group of related pathologic conditions,such as HLT Eosinophilic disorders, which shares a place under HLGT White blood
cell disorders with other HLTs mostly related (though not always) to blood peripheral
findings.
6.1.2 Conventions and Exceptions
The representation of hematologic neoplasms is identical to the hierarchy developed
for the same terms within SOC Neoplasms benign, malignant and unspecified (inclcysts and polyps). Lymphoma classification in MedDRA at the PT level and above
follows the Revised European-American Lymphoma (R.E.A.L.) Classification. The
Working Formulation classification is limited to the LLT level.
All lymphatic system-related disorders have their primary link to SOC Blood andlymphatic system disorders except infective and congenital disorders. (Lymphoma
terms do not follow this convention).
6.1.3 Search Strategies
If a search is intended to cover an overall classification of anemias, then in addition to
HLGT Anaemias nonhaemolytic and marrow depression, both HLGT
Haemoglobinopathies and HLGT Haemolyses and related conditions should also be
considered. In a similar situation, when looking for a general view of “bleeding
diatheses,” consider searching under HLGT Coagulopathies and bleeding diatheses(excl thrombocytopenic), and HLGT Platelet disorders (especially HLT
Thrombocytopenias).

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6.2

CARDIAC DISORDERS

6.2.1 Basis for Classification
The division of HLGTs within this SOC has been done partly on an anatomic basis(endocardial, myocardial and pericardial disorders, coronary artery disorders, and valve
disorders) and partly by pathophysiology (neoplasms, arrhythmias, cardiac failure,congenital cardiac disorders, and cardiac signs and symptoms). HLTs are grouped bypathophysiology, with the exception of valve disorders, which are grouped anatomicallyby the valve affected.
6.2.2 Conventions and Exceptions
All congenital cardiac disorders are placed within HLGT Congenital cardiac disorders.
Thus, HLGT Cardiac valve disorders contains only those cardiac valve disorders thatare not specified as congenital.
Certain congenital anomalies include both cardiac and vascular components. These
terms have been linked to HLT Congenital cardiovascular disorders NEC (with HLGTCongenital cardiac disorders linking it to SOC Cardiac disorders).
Electrocardiogram (ECG) results are not included in SOC Cardiac disorders; they aregrouped in HLT ECG Investigations within SOC Investigations.
Auscultatory abnormalities are grouped in HLT Cardiac auscultatory investigations
under HLGT Cardiac and vascular investigations (excl enzyme tests) in SOC
Investigations.
For the major body systems of cardiac, hepatic, pulmonary, and renal, the terms“failure” and “insufficiency” are used synonymously. In SOC Cardiac disorders, the“failure” term is at the PT level and the “insufficiency” term is at the LLT level (e.g., PT
Cardiac failure and LLT Cardiac insufficiency).

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6.3

CONGENITAL, FAMILIAL AND GENETIC DISORDERS

6.3.1 Basis for Classification
The terms within this SOC are primarily divided anatomically at the HLGT level. Where
possible, these divisions at the HLGT level reflect the system organ classes used in
MedDRA as a whole (e.g., HLGT Hepatobiliary disorders congenital and HLGTEndocrine disorders congenital are the names of SOCs with “congenital” added).
Exceptions to this are HLGT Chromosomal abnormalities, gene alterations and genevariants (which replaced HLGT Chromosomal abnormalities and abnormal gene carriers
in Version 23.0), HLGT Congenital and hereditary disorders NEC, and HLGT
Cytoplasmic disorders congenital. At the HLT level, terms are further subdivided byanatomy wherever possible (e.g., HLT Thyroid disorders congenital). For those HLGTs
that cannot be divided by anatomy (e.g., HLGT Metabolic and nutritional disorderscongenital), PTs are grouped in HLTs by disease process (e.g., HLT Inborn errors ofbilirubin metabolism) or, in the case of HLGT Infections and infestations congenital, by
type of organism (e.g., HLT Bacterial infections congenital).
In Version 23.0, several terminology grouping changes were incorporated in SOC
Congenital, familial and genetic disorders to refine the hierarchical placement of genetic
terms. HLGT Chromosomal abnormalities and abnormal gene carriers was replacedwith HLGT Chromosomal abnormalities, gene alterations and gene variants to represent
that SOC Congenital, familial and genetic disorders is intended to cover gene concepts,
whether they are acquired or congenital.
HLT Gene mutations and other alterations NEC was added to the new HLGT
Chromosomal abnormalities, gene alterations and gene variants, and former HLT
Acquired gene mutations and other alterations was merged into HLT Gene mutations
and other alterations NEC in Version 23.0. This HLT groups all gene conditions andalterations such as overexpressions, rearrangements, and mutations together,regardless of whether they are congenital or acquired, and separates gene concepts
from chromosomal concepts which are represented in other HLTs of SOC Congenital,familial and genetic disorders.
Also in Version 23.0, HLT Genetic polymorphisms was added to HLGT Chromosomal
abnormalities, gene alterations and gene variants. The creation of an HLT for genetic
polymorphisms, which are considered as gene variants rather than gene alterations,aids in the coding and retrieval of these concepts.
6.3.2 Conventions and Exceptions
In MedDRA, the term “congenital” is used to describe any condition present at birth,whether genetically inherited or occurring in utero.
Most MedDRA terms representing congenital, familial, and genetic disorders havemanifestations in more than one system or organ class. Since a term can only appear
in one HLT within a SOC, the HLT for these terms has been selected according to themost clinically significant manifestation of that disorder. Additionally these terms
typically have SOC Congenital, familial and genetic disorders as their primary SOC.
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However, they will have links to secondary SOCs as usual in the multi-axial structure.
For example, PT Congenital HIV infection links to four SOCs: SOC Congenital, familial
and genetic disorders (primary), SOC Pregnancy, puerperium and perinatal conditions,
SOC Immune system disorders, and SOC Infections and infestations.
For conditions or diseases existing in both congenital and acquired forms, the following
convention is applied: the more common form of the condition/disease is represented at
the PT level without adding a qualifier of either “congenital” or “acquired.” For example,
hypothyroidism is more commonly acquired than congenital; therefore, the unqualified
term is at the PT level (PT Hypothyroidism). The less common form of the condition ordisease will also be at the PT level but with a qualifier added. Using again the exampleof hypothyroidism, the less common congenital form has the qualifier “congenital” at the
PT level (PT Congenital hypothyroidism). The addition of qualified LLTs under the non
qualified PT term is limited in MedDRA. The qualified LLTs will only be added ininstances where the likelihood of occurrence of congenital and acquired condition isclose to being the same. Alignment of existing affected terms along the lines describedabove (i.e., the “acquired,” "congenital,” and unqualified terms) has already been carriedout in MedDRA Version 8.0. The subscriber Change Request process will drive theremainder of alignments of possible term sets.

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6.4

EAR AND LABYRINTH DISORDERS

6.4.1 Basis for Classification
The terms within this SOC are primarily divided at the HLGT level by anatomic site(external, middle, and inner ear). At the HLT level, terms are further subdivided
anatomically, but the disease process may also be reflected at this level (e.g., HLT
Middle ear infections and inflammations). Congenital problems are grouped in HLGTCongenital ear disorders (excl deafness), which is subdivided into HLTs by anatomic
criteria. Non-site specific terms are linked to HLGT Hearing disorders.
6.4.2 Conventions and Exceptions
The PTs for neoplasms appear in the appropriate HLT by anatomic site (e.g., PT Benign
middle ear neoplasm appears in HLT Middle ear disorders NEC).
Infections and inflammations are grouped at the HLT level in the HLGT External ear
disorders (excl congenital), HLGT Middle ear disorders (excl congenital), and HLGT
Inner ear and VIIIth cranial nerve disorders.
The pinna, which includes the ear lobe, is considered part of the ear structure and isprimarily linked to SOC Ear and labyrinth disorders.

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6.5

ENDOCRINE DISORDERS

6.5.1 Basis for Classification
Endocrine disorders are classified using two general approaches. The first approachgroups HLTs specific to the dysfunction of a specific endocrine gland under an HLGT
specific to that gland. For example, HLGT Adrenal gland disorders is superordinated to
HLT Adrenal cortical hyperfunctions, HLT Adrenal cortical hypofunctions, HLT Adrenal
gland disorders NEC, HLT Adrenal medulla disorders, and HLT Adrenal neoplasms.
HLT Adrenal gland disorders NEC contains terms relating to adrenal gland infections,injuries, and congenital disorders. These terms have secondary links to SOC Endocrine
disorders.
The second type of classification includes HLGTs that group disorders affecting multiple
endocrine glands, such as HLGT Endocrine and glandular disorders NEC and HLGT
Neoplastic and ectopic endocrinopathies.
Within HLGT Endocrine and glandular disorders NEC, HLT Endocrine disorders NEC
includes congenital and myopathic disorders with primary links to their respective
SOCs. HLT Polyglandular endocrine disorders contains terms for conditions involving
multiple endocrine glands.
HLGT Endocrine disorders of gonadal function includes HLTs covering male disorders,female disorders, and gender unspecified disorders as well as disorders occurring at
puberty. Many of the terms here are primarily linked to the body system SOC that is
affected, with secondary links to SOC Endocrine disorders.
6.5.2 Conventions and Exceptions
There are two separate HLGTs that relate to diabetes: HLGT Glucose metabolism
disorders (incl diabetes mellitus), with HLTs for diabetes mellitus and both hypo- andhyperglycemic conditions; and HLGT Diabetic complications, which subdivides thecomplications of the disease anatomically. These two HLGTs are multi-axial and arealso linked to SOC Metabolism and nutrition disorders.
Pancreatic endocrine disorders are linked primarily to SOC Endocrine disorders,
whereas pancreatic exocrine disorders are linked primarily to SOC Gastrointestinal
disorders. If the term does not distinguish between endocrine and exocrine, then the
primary link defaults to SOC Gastrointestinal disorders (e.g., PT Pancreatic disorder).

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6.6

EYE DISORDERS

6.6.1 Basis for Classification
SOC Eye disorders is subdivided along pathophysiologic and anatomic lines. The
primary ordering of the HLGTs is according to pathophysiology, e.g., HLGT Ocular
infections, irritations and inflammations and HLGT Ocular neoplasms. Bothpathophysiology and anatomy are used to approach the classification of other HLGTs,
which are disorders occurring in specific tissues of the eye, e.g., structural change,
deposit, or degeneration of the anterior portion of the eye, or vascular disorder andhemorrhage of retina, choroids, or vitreous. HLGTs using pathophysiology fororganization are subdivided using anatomically classified HLTs. For example, under
HLGT Ocular injuries is HLT Corneal injuries. In HLGTs using the pathophysiologic andanatomic organization, HLTs are also further classified anatomically. Eyelid, lash, andlacrimal disorders are included in this SOC under the appropriate pathophysiologic
HLGTs.
HLGT Congenital eye disorders (excl glaucoma) is inclusive of all congenital eye
disorders with the exception of glaucoma. HLT Congenital glaucomas is located undera separate HLGT, namely, HLGT Glaucoma and ocular hypertension. All congenital
eye terms have a secondary linkage to SOC Eye disorders.
HLGT Eye disorders NEC contains a mixture of HLTs based on both anatomy andetiology (e.g., HLT Corneal disorders NEC ). This HLGT contains those medical
concepts that are of an unspecified nature as well as those terms related to eye
structures that do not fall within the HLGT classification scheme.
HLGT Vision disorders is segmented primarily by pathophysiology and contains terms
that describe the etiology of visual disorders, such as HLT Amblyopic vision impairment,
HLT Refractive and accommodative disorders, HLT Colour blindness (incl acquired),and HLT Visual impairment and blindness (excl colour blindness).
HLGT Ocular neoplasms is subdivided pathophysiologically according to tumor type.
Note that there are hierarchical classifications in other SOCs that include terms of
relevance to ophthalmologic concepts. Such terms merit consideration when designingsearch strategies and data retrieval and analysis criteria for terms pertaining to eye
disorders. Examples include:






SOC Nervous system disorders: HLGT Neurological disorders of the eye;
SOC Surgical and medical procedures: HLGT Eye therapeutic procedures;
SOC General disorders and administration site conditions: HLT Eye
complications associated with device;
SOC Injury, poisoning and procedural complications: HLT Eye and ear
procedural complications;
SOC Investigations: HLT Ophthalmic function diagnostic procedures, HLT
Ophthalmic histopathology and imaging procedures, PT Ophthalmological

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examination abnormal (under HLT Physical examination procedures and organsystem status).
6.6.2 Conventions and Exceptions
PT Blindness is linked to HLGT Vision disorders. To make a distinction between
blindness as a disability and blindness as a medical disorder, PT Sight disability islinked to SOC Social circumstances (blindness as a disability) and PT Blindness islinked to SOC Eye disorders (blindness as a medical disorder) and to SOC Nervous
system disorders .
The eyelid is classified as a structure of the eye. In general, terms related to the eyelid
are primarily linked to SOC Eye Disorders and secondarily to SOC Skin andsubcutaneous tissue disorders.

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6.7

GASTROINTESTINAL DISORDERS

6.7.1 Basis for Classification
There are three principles for classification in this SOC. Terms are gathered at the
HLGT level by a mix of disease process, etiology, and pathologic groupings (e.g., HLGT
Abdominal hernias and other abdominal wall conditions, HLGT Gastrointestinal
infections, and HLGT Gastrointestinal ulceration and perforation). These HLGTs are
subdivided into HLTs by anatomic site or subtypes of the disease process. For
instance, HLGT Gastrointestinal infections contains HLTs based on anatomic site (analand rectal, intestinal, esophageal, etc.), but HLGT Gastrointestinal motility anddefaecation conditions has HLTs reflecting the disease process (e.g., HLT
Gastrointestinal dyskinetic disorders). Neoplasm terms are linked to HLGT Benign
neoplasms gastrointestinal and to HLGT Malignant and unspecified neoplasms
gastrointestinal NEC. The remaining HLGTs are based on anatomic site (HLGT Oralsoft tissue conditions) with HLTs denoting further anatomic specificity (HLT Cleft lip andcleft palate disorders), disease process (HLT Stomatitis and ulceration), or a
combination of both (HLT Oral soft tissue signs and symptoms).
6.7.2 Conventions and Exceptions
HLGT Gastrointestinal infections and HLGT Gastrointestinal inflammatory conditions
are separate HLGTs in SOC Gastrointestinal disorders. In other SOCs, inflammatory
and infectious conditions are often within a single HLGT (e.g., HLGT Ocular infections,
irritations and inflammations in SOC Eye disorders). Pancreatic endocrine disorders
are linked primarily to SOC Endocrine disorders. Pancreatic exocrine disorders arelinked primarily to SOC Gastrointestinal disorders. If the term does not distinguishbetween endocrine and exocrine, then the primary link defaults to SOC Gastrointestinal
disorders (e.g., PT Pancreatic disorder).
“Perineum” terms may be linked to several SOCs including SOC Reproductive systemand breast disorders and SOC Pregnancy, puerperium and perinatal conditions. Newly
added “perineum” terms resulting from Change Requests are linked to their mostappropriate classification on a case-by-case basis.

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6.8

GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS

6.8.1 Basis for Classification
This SOC contains terms that do not readily fit into the hierarchy of any one SOC or arenonspecific disorders that impact several body systems or sites. HLGTs within it are
divided by etiology (therapeutic and non-therapeutic effects and administration site
reactions) or pathology (fatal outcomes and tissue conditions). The HLTs within each
HLGT are mainly divided by disease process. Exceptions are HLGT Administration site
reactions, which is divided by type of administration - (application, implant, and injectionsite); and HLGT Therapeutic and nontherapeutic effects (excl toxicity), which is groupedby type of effect (e.g., HLT Interactions and HLT Therapeutic and nontherapeutic
responses). HLT Therapeutic and nontherapeutic responses is a broad HLT intended tocapture terms in MedDRA that cannot be placed in any other specific HLT grouping(e.g., PT Therapeutic product effect decreased and PT Drug ineffective). Terms related
to specific drugs, drug related issue, specific site of manifestation or specific condition
will be placed according to the established placement rules in MedDRA (e.g., PT
Oestrogenic effect is mapped to primary HLT Endocrine abnormalities of gonadal
function NEC, which represents the site of manifestation).
In MedDRA Version 19.0, grouping terms relating to product quality issues and device
issues have been moved from this SOC to the new SOC Product issues which was
created to accommodate non-clinical/non-patient related concepts. Specifically, HLGT
Product quality, supply, distribution, manufacturing and quality system issues with its
five subordinate HLTs (HLT Product contamination and sterility issues, HLT Productlabel issues, HLT Product packaging issues, HLT Product physical issues, and HLT
Product quality issues NEC) has been merged with new HLGT Product quality, supply,
distribution, manufacturing and quality system issues in SOC Product issues.
Additionally, HLGT Device issues has been moved to SOC Product issues with all its
eight subordinate HLTs (HLT Device computer issues, HLT Device electrical issues,
HLT Device incompatibility issues, HLT Device information output issues, HLT Device
issues NEC, HLT Device malfunction events NEC, HLT Device operational issues NEC,and HLT Device physical property and chemical issues).

6.8.2 Conventions and Exceptions
Representing PTs in SOC General disorders and administration site conditions in eachpotential secondary SOC would create an inordinately large number of multi-axial links.
Therefore, most of the PTs in this SOC are primarily linked to SOC General disorders
and administration site conditions, and have limited representation in secondary SOCs
(e.g., PT Injection site atrophy is primarily to SOC General disorders and administrationsite conditions and secondarily only to SOC Injury, poisoning and procedural
complications). There are a number of PTs in this SOC that are non-multi-axial due totheir general nature (e.g., PT Fatigue, PT Malaise, and PT Discomfort).
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LLT High temperature is in SOC General disorders and administration site conditions.
Although the concept should appear in SOC Investigations by convention (i.e., it could
be interpreted as a measured parameter), it is most frequently used as an expression
for fever (PT Pyrexia). Thus, this term is represented in SOC General disorders andadministration site conditions.
HLGT Complications associated with device is used to capture patient reactions that
occur during the use of a medical device (may or may not be directly attributable to theuse of the device) and events that are a direct consequence of use of the medical
device. In general, medical device event concepts are represented at the PT level,
while corresponding sub-concepts pertaining to events with specific types of widelyused devices are usually represented at the LLT level.
.

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6.9

HEPATOBILIARY DISORDERS

6.9.1 Basis for Classification
The terms in this SOC are grouped under four HLGTs. Three of these HLGTs aregrouped by anatomic location and are subdivided into HLTs reflecting the etiology or
disease process. For example, HLGT Bile duct disorders includes HLT Bile duct
infections and inflammations, HLT Obstructive bile duct disorders (excl neoplasms), andHLT Structural and other bile duct disorders. The remaining HLGT is HLGTHepatobiliary neoplasms, distinguishing between benign and malignant neoplasms andneoplasms with unspecified characteristics at the HLT level.
Two spellings, “hepato-biliary” and “hepatobiliary,” are used frequently in practice.
MedDRA uses “hepatobiliary,” following Dorland's Illustrated Medical Dictionary.
For the major body systems of cardiac, hepatic, pulmonary, and renal, the terms“failure” and “insufficiency” are used synonymously. In SOC Hepatobiliary disorders, the“failure” term is at the PT level and the “insufficiency” term is at the LLT level (e.g., PT
Hepatic failure and LLT Hepatic insufficiency).

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6.10 IMMUNE SYSTEM DISORDERS
6.10.1 Basis for Classification
The terms within this SOC are divided by disease process. The HLGTs are HLGTAllergic conditions, HLGT Autoimmune disorders, HLGT Immune disorders NEC, and
HLGT Immunodeficiency syndromes. Further sub-classification at the HLT level is bypathologic groupings, with some anatomically based subdivision as in the case of HLGT
Autoimmune disorders.
6.10.2 Conventions and Exceptions
Only very well defined secondary immunodeficiencies have been included under HLT
Immunodeficiency disorders NEC. The link of all possible immunodeficiencies under
this HLT would result in too large a group for analytical purposes.
The concept of transplant rejection is recognized as an effect of the immune system;
therefore, related terms have SOC Immune system disorders as the primary link withthe site of manifestation as a secondary link.
Due to the systemic nature of SOC Immune system disorders, multi-axial terms areespecially frequent. For instance, conditions related to the group of “connective tissue
disorders” are found under HLGT Autoimmune disorders as well as in SOC
Musculoskeletal and connective tissue disorders (in HLGT Connective tissue disorders(excl congenital)), with still a possible third link in the related anatomic SOCs (generally
the primary link). For instance, PT Lupus vasculitis has the following links:

PT
Lupus
vasculitis

HLT

HLGT

SOC

Link

Vasculitides NEC

Vascular
infections andinflammations

VasculardisordersPrimary

Lupus erythematosus(incl subtypes)

Connective
tissue disorders(excl congenital)

Musculoskeletaland connective
tissue disorders

SecondaryLupus erythematosus
and associatedconditions

Autoimmune
disorders

Immune systemdisorders

Secondary

Table 6-1. Sample of Exceptions and Conventions in SOC Immune System
Disorders

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Other pathologic groupings within SOC Immune system disorders, in which a similar
multi-axial richness can be found, are transplant rejection terms (that are also in SOC
Injury, poisoning and procedural complications linked to HLGT Procedural related
injuries and complications NEC). Transplant terms are also linked to their respective
anatomic site SOCs. HLT Vasculitides (SOC Immune system disorders) has its
counterpart in SOC Vascular disorders grouping terms (see HLT Vasculitides NEC in
HLGT Vascular infections and inflammations); terms linked to this HLT are also found in
the associated anatomic SOCs.

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6.11

INFECTIONS AND INFESTATIONS

6.11.1 Basis for Classification
SOC Infections and infestations were developed to provide a unique location forinfectious disorders and related conditions. The organization of this SOC at the HLGTlevel is based on broad, commonly used taxonomic classifications of pathogens (e.g.,
HLGT Bacterial infectious disorders, HLGT Fungal infectious disorders, and HLGT
Ectoparasitic disorders). At the HLT level, these groups are further sub-classified bygenus in most cases for bacterial, protozoal, fungal, and viral disorders (e.g., HLT
Candida infections).
One general HLGT, HLGT Infections - pathogen unspecified is used to group together
infections by anatomic location rather than pathogen class. The HLTs under this HLGT
are named according to general anatomic location, such as HLT Bone and joint
infections. However, diseases of specific anatomic locations caused by specified
pathogens are classified under the name of the pathogen, and not under thecorresponding anatomic location in this HLGT.
6.11.2 Conventions and Exceptions
Most PTs in SOC Infections and infestations are primarily linked to this SOC.
Exceptions are PTs that have a primary link to either SOC Congenital, familial andgenetic disorders or SOC Neoplasms benign, malignant and unspecified (incl cysts andpolyps). For these terms, the link to SOC Infections and infestations is secondary.
Additionally, PTs under HLT Inflammatory disorders following infection within HLGT
Ancillary infectious topics may also have a secondary link to SOC Infections andinfestations. This HLGT does not include PTs representing infections or infestations but
instead includes PTs that are very closely related such as PT Infectious disease carrier;it also has terms representing types of infectious transmission (e.g., PT Air-borne
transmission) or inflammatory conditions following an infection (e.g., PT Rheumatic
fever).
Terms ending with “-itis” are linked to SOC Infections and infestations only if they mostfrequently represent infectious conditions (PT Tonsillitis). Those terms that mostfrequently represent inflammatory conditions (e.g., PT Arteritis) are linked to theircorresponding site of manifestation SOCs without a primary link to SOC Infections andinfestations.
In general, pathogen genus is represented at the HLT level (e.g., HLT Mycoplasma
infections). The PT level generally combines genus and anatomic site of infection in asingle term (e.g., PT Pharyngitis mycoplasmal), Genus, anatomic site, and species aredesignated in a single term at the LLT level (e.g., LLT Mycoplasma pneumoniae
pharyngitis).
When the concepts of “sepsis” and “septic(a)emia” are paired in the terminology, the“sepsis” terms are PTs and the corresponding “septic(a)emia” terms are LLTs.

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Terms with “gangrene” or “gangrenous” have a primary link to SOC Infections andinfestations, except those specifically representative of a noninfective concept (e.g. PT
Dry gangrene).
Within SOC Infections and infestations, PT level “cellulitis” terms are linked to theappropriate bacterial infection HLTs rather than the site of manifestation HLTs.
6.11.3 Search Strategies
For a search of opportunistic infections, the underlying disease, drug class, and otheraspects possibly relevant to the question should be considered when selecting terms
from MedDRA. For example, the most likely pathogen or the body site affected may
differ depending on the cause of immunosuppression (e.g., HIV infection, solid organtransplant, hematopoietic stem cell transplant, malignancy, chemotherapy, TNF-alfa
blockers, etc.), geographical region, and calendar year/decade (due to changes ofprominence of pathogens over time). As a starting point, SOC Infections andinfestations should be reviewed multi-axially.
For a narrow (specific) search, it may suffice to restrict the search to certain terms in
SOC Infections and infestations
If taking a broad approach, all terms in SOC Infections and infestations may be includedin the search, including terms not indicating the causative agent (e.g., PT Pneumonia or
PT Sepsis). Additionally, relevant terms may be found in SOC Investigations, such aslaboratory abnormality terms in HLGT Microbiology and serology investigations.
Additional terms may be relevant for inclusion for specific conditions as in the following
examples:For an underlying HIV infection, many PTs containing "HIV," "AIDS," "CD4," or "Tlymphocyte" may be added, plus PT Immune reconstitution inflammatory syndrome.
For an underlying solid organ transplant or hematopoietic stem cell transplant, certain
PTs containing "transplant" or "graft" may be relevant.
For an underlying malignancy, SOC Neoplasms benign, malignant and unspecified (inclcysts and polyps) may be reviewed; certain PTs indicating neutropenia and resulting
complications secondary to chemotherapy may be added to the search.

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6.12 INJURY, POISONING AND PROCEDURAL COMPLICATIONS
6.12.1 Basis for Classification
This SOC provides a grouping for those medical concepts where an injury, poisoning,procedural, or device complication factor is significant in the medical event being
reported.
Terms that represent events directly attributed to trauma, poisoning, and procedural
complications are primarily linked to SOC Injury, poisoning and procedural
complications, with the exception of terms related to birth trauma such as PT Facial
nerve injury due to birth trauma, which is primary to SOC Pregnancy, puerperium andperinatal conditions. Bone fractures, which in most cases are attributed to trauma, areprimary to this SOC, whereas pathologic and osteoporotic fractures are primary to SOC
Musculoskeletal and connective tissue disorders. Terms in HLT Poisoning and toxicity
under HLGT Exposures, chemical injuries and poisoning are generally primarily linked
to this SOC, except when the body system is identified by the text string of the term. In
these cases, the SOC representing the site of manifestation is primary. An example ofthis is “toxic nephropathy,” which could be an adverse event due to an external agent or
to an internal organ condition. (PT Nephropathy toxic is linked primarily to SOC Renal
and urinary disorders and secondarily to SOC Injury, poisoning and procedural
complications.)
Injury and damage concepts were discussed by a MedDRA Expert Panel which resulted
in new guidelines for MedDRA. Based on this, injury and damage terms in MedDRA
are considered generally as synonymous. Injury or damage to a major organ that has alow probability for a traumatic causality will be placed primary to the site ofmanifestation, unless causality ”due to accident” is the more obvious or the mostprobable. In this case, the term will be linked primary to SOC Injury, poisoning andprocedural complications. Following this guidance some liver injury terms were realigned. PT Cholestatic liver injury, PT Mixed liver injury, and PT Liver injury are
considered non-traumatic and are primarily linked to SOC Hepatobiliary disorders while
PT Traumatic liver injury is primarily linked to SOC Injury, poisoning and procedural
complications.
A distinction has been made between exposure “to” versus exposure “via” terms (e.g.,
PT Exposure to body fluid and PT Exposure via body fluid) because this distinction isrelevant to the representation of different exposure concepts and is of particularsignificance to toxicologic elements of pharmacovigilance. While the difference
between “via” and “to” may appear subtle, the “via” terms indicate the vehicle by which
the patient is exposed whereas “to” concepts identify the specific agent of exposure.
For example, PT Exposure to body fluid might be used to code medical history, when it
may not be known whether the body fluid was infectious or contained some otherharmful element. The “via” terms are meant to be used in combination with one or more
additional term(s), for example, to code the agent of exposure, such as LLT Hepatitis B,
and any resulting clinical consequences, such as LLT Jaundice.

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HLGT Procedural related injuries and complications NEC groups terms related tosurgical and medical therapeutic procedures. The HLTs are mainly groupedanatomically, but there are also procedure-specific term groupings such as HLT
Induced abortion complications and HLT Anaesthetic and allied procedural
complications.
HLGT Administration site reactions is a multi-axial HLGT. It is primarily linked to SOC
General disorders and administration site conditions. This HLGT is also linked(secondarily) to SOC Injury, poisoning and procedural complications for the purpose ofproviding a common SOC linkage with surgical and medical treatment types ofprocedural complications that are typically found only in this SOC. HLGT Administrationsite reactions is sub-grouped into HLT Application and instillation site reactions, HLT
Implant and catheter site reactions, HLT Injection site reactions, HLT Infusion site
reactions, HLT Vaccination site reactions and HLT Administration site reactions NEC.
Medical practitioners frequently use the words “poisoning” and “toxicity”
interchangeably. Based upon this common usage of the words, a distinction is notmade between poisoning and toxicity in MedDRA. Instead, these types of terms areboth grouped under HLT Poisoning and toxicity.
The hierarchy for medication error and product use issues was revised in MedDRA
Version 20.0 to group errors and unspecified use issues separately from intentional use
issues.
HLGT Medication errors and other product use errors and issues is subdivided into HLTgroupings based on the types of errors and issues and includes the various stages in
the medication/product use process (prescribing, storage, dispensing, preparation foradministration, and administration). The subordinate HLTs are HLT Accidental
exposures to product, HLT Medication errors, product use errors and issues NEC, HLT
Product administration errors and issues, HLT Product confusion errors and issues,
HLT Product dispensing errors and issues, HLT Product monitoring errors and issues,
HLT Product preparation errors and issues, HLT Product prescribing errors and issues,
HLT Product selection errors and issues, HLT Product storage errors and issues in the
product use system, and HLT Product transcribing errors and communication issues.
HLGT Off label uses and intentional product misuses/use issues is subdivided into HLTIntentional product misuses, HLT Intentional product use issues, and HLT Off label
uses.
HLGT Overdoses and underdoses NEC groups terms for intentional and unspecified
overdoses and underdoses.The subordinate HLTs are HLT Overdoses NEC and HLT
Underdoses NEC. Accidental overdose and underdose terms are grouped under HLT
Product administration errors and issues.
6.12.2 Conventions and Exceptions
HLGT Bone and joint injuries is an exception to the general organization of this SOC.
This HLGT is not aligned anatomically under HLGT Injuries NEC in the way that theother body systems are grouped. This has been done for two reasons: 1) the skeletal
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system is frequently and significantly impacted by traumatic injuries; and 2) thisadditional level of classification allows a better linking to SOC Musculoskeletal andconnective tissue disorders.
Most terms representing chemical injuries are only in this SOC, while many of the otherinjury terms are multi-axial with a secondary linkage to their respective site ofmanifestation.
Although terms for acute alcohol intoxication or poisoning are found in this SOC, theconcept of ”alcoholism” is represented in SOC Psychiatric disorders as PT Alcoholism.

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6.13 INVESTIGATIONS
6.13.1 Basis for Classification
The most significant characteristics of SOC Investigations are: 1) its content (i.e.,
investigations, not conditions); and 2) its single-axial nature. For MedDRA, an“investigation” is a clinical laboratory test concept (including biopsies), radiologic test
concept, physical examination parameter, and physiologic test concept (e.g., pulmonary
function test).
Only PTs representing investigation procedures and qualitative results (e.g., PT Bloodsodium decreased, PT Blood glucose normal) appear in SOC Investigations. Terms
representing conditions (e.g., hyperglycemia) or mixed concepts of conditions with aninvestigation are excluded from this SOC and can be found in the respective “disorder”
SOCs (e.g., PT Hyperosmolar state, PT Haemosiderosis, PT Orthostatic proteinuria,
and PT Renal glycosuria).
Terms in SOC Investigations are present only in this SOC and in no other SOC (i.e.,
SOC Investigations is single-axial). Therefore, it is important that queries of MedDRAcoded data encompass terms from both the “disorder” SOCs (e.g., PT
Thrombocytopenia in SOC Blood and lymphatic system disorders) as well as the
supporting investigation concepts in SOC Investigations (e.g., PT Platelet countdecreased) since one cannot exploit multi-axial links to bridge these types of terms.
Several classification approaches to HLGTs are used in this SOC:

 Some HLGTs group investigations according to body system or according to theclinical discipline commonly specializing in a particular body system (e.g., HLGTSkin investigations, HLGT Gastrointestinal investigations, and HLGTHaematology investigations (incl blood groups)).

 Other HLGTs group (by type of substance, or by type of procedure) thoseanalyses or investigations that do not fit readily into a single body system (e.g.,
HLGT Water, electrolyte and mineral investigations, HLGT Lipid analyses, HLGT
Toxicology and therapeutic drug monitoring, HLGT Cytogenetic investigations,and HLGT Physical examination and organ system status topics).

 Three HLGTs include terms for investigations which are not classified elsewhere:


HLGT Enzyme investigations NEC groups tests that are commonly used to
identify abnormalities in several body systems (e.g., HLT Tissue enzyme
analyses NEC contains alkaline phosphatase tests for bone or liver disorders,
while HLT Skeletal and cardiac muscle analyses contains creatine kinase
isoenzyme terms related to heart, skeletal muscle, and brain tissue).



HLGT Investigations, imaging and histopathology procedures NEC includes
terms describing laboratory test interference as well as terms covering
unspecified laboratory investigations and imaging, and pathology procedures
without a specified site.

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

HLGT Protein and chemistry analyses NEC includes specific protein analyses
that are not usually associated with single system disorders (e.g., albumin
tests and turbidity tests) as well as renin and angiotensin tests.

 HLGT Foetal and neonatal investigations groups all fetal and neonatal
investigations and procedures. It includes HLTs for diagnostic, histopathologic,
and imaging procedures.

 HLT Physical examination procedures and organ system status, linked to HLGT
Physical examination and organ system status topics, includes parameters
measured (e.g., body temperature and body weight), and conditions found (e.g.,abnormal prostate examination and hypophonesis) during physical examination.
HLTs in this SOC are generally self-explanatory. They are based on a variety of
approaches: Some HLTs group diagnostic procedures (e.g., HLT Cardiac function diagnostic
procedures), imaging procedures (e.g., HLT Gastrointestinal and abdominal
imaging procedures), or pathology procedures (e.g., HLT Musculoskeletal andsoft tissue histopathology procedures). Note, however, that some of thediagnostic procedure HLTs include imaging procedures (e.g., HLT Ophthalmic
function diagnostic procedures includes PT Angiogram retina).

 For some HLTs, anatomic site or tissue type is used for grouping (e.g., HLT
Adrenal cortex tests, HLT Cerebrospinal fluid tests (excl microbiology)). In such
instances diagnostic, imaging, or histopathology procedures may be included
within one HLT (e.g., HLT Urinary tract function analyses NEC).

 Other HLTs group tests of related analytes or parameters (e.g., HLT Lysosomal
enzyme analyses, HLT Water and electrolyte analyses NEC, HLT Platelet
analyses, HLT Fungus identification and serology).

 The following are some additional specific characteristics of SOC Investigations:

Diaphragm and mediastinum – Diaphragm pathology procedures andmediastinal pathology procedures are found in HLT Respiratory tract andthoracic histopathology procedures under HLGT Respiratory and pulmonary
investigations (excl blood gases).



Gastrin – Gastrin tests are included in HLT Gastrointestinal, pancreatic and
APUD hormone analyses in HLGT Endocrine investigations (incl sex
hormones).



Laparoscopy – PT Laparoscopy appears within HLT Gastrointestinal andabdominal imaging procedures under HLGT Gastrointestinal investigations.



Lymph nodes - Lymph node scans and lymph gland histopathology
procedures are included in HLT Bone marrow and immune tissue imaging
procedures and HLT Bone marrow and immune tissue histopathology
procedures in HLGT Haematology investigations (incl blood groups).

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Red blood cell sedimentation rate – PT Red blood cell sedimentation rate
is found within HLT Haematological analyses NEC.



Urea – Tests for urea are linked to HLGT Renal and urinary tract
investigations and urinalyses, either within HLT Renal function analyses or
HLT Urinalysis NEC.

Where possible, PTs in this SOC are those included in IUPAC, LOINC, and IFCC
standards. However, in some cases, texts of terms from these standard terminologies
are not the commonly used wording by practitioners. In these instances, the text strings
used in MedDRA are the ones more commonly used in practice. In some cases, natural
language has been used in preference to technical correctness to avoid confusion (e.g.,
PT Activated partial thromboplastin time instead of the IUPAC term “Coagulation,
surface induced”). Vitamins are represented by their common names rather than by thechemical names used in IUPAC.
6.13.2 Conventions and Exceptions
The qualifier “increased” in MedDRA terms refers to changes from normal state to high,from low to normal, from low to high, and from low normal to high normal. Similar
considerations apply to results that are “decreased.” MedDRA investigation terms use
the qualifiers of “low” and “high” at the LLT level only; these LLTs with “low” and “high”
are linked to PTs with qualifiers of “decreased” and “increased” respectively.
Additionally, qualifiers "low/decreased" and “high/increased” in SOC Investigations are
considered synonyms.
“High and “low” terms in MedDRA are generally considered to belaboratory/investigation type of terms and are found in the SOC Investigations.
Exceptions to this rule are as follows: LLT Blood pressure high and LLT Low blood pressure are linked to PT
Hypertension or PT Hypotension; these PTs are in SOC Vascular disorders.

 PTs representing “low grade” neoplasms are linked to SOC Neoplasms benign,malignant and unspecified (incl cysts and polyps) (e.g., PT Astrocytoma, lowgrade).

 PT Sputum decreased and PT Sputum increased are in SOC Respiratory,
thoracic and mediastinal disorders. This is because these terms commonly
express a medical condition rather than an investigation finding.

 LLT High temperature is in SOC General disorders and administration site
conditions. Although the concept should appear in SOC Investigations by
convention (i.e., it could be interpreted as a measured parameter), it is mostfrequently used as an expression for fever (PT Pyrexia); thus, this term is in SOC
General disorders and administration site conditions.
The qualifier “abnormal” in a MedDRA term represents a situation where the “direction”(i.e., increased or decreased) of the abnormal result is not specified. Other qualifiers
used in SOC Investigations are “normal,” “present,” or “absent” for descriptive laboratory
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tests (e.g., PT Blood urine absent), “positive” or “negative” for qualitative tests (e.g., PT
Pregnancy test positive), “prolonged,” or “shortened” for tests measured in time (e.g.,
LLT APTT prolonged), and “toxic,” “therapeutic,” or “subtherapeutic” for drug levelmonitoring tests (e.g., PT Drug level below therapeutic). An unqualified term (e.g., PT
Oxygen saturation, PT pH urine) may be used to point to an actual value in a separate
database field. Terms containing the prefixes “hyper-” and “hypo-” (e.g., PT
Hypercholesterolaemia, PT Hyponatraemia) are found in their respective “disorder”
SOCs and not in SOC Investigations.
If an analyte is not normally present in a specimen, the PT describing that abnormality
may be used in some cases (e.g., PT Glucose urine present).
For specimen identification, the noun form of the specimen name is used (“urine
cortisol,” not “urinary cortisol”) in SOC Investigations.
As of MedDRA Version 7.0, there has been a change to the MSSO convention foradding terms to SOC Investigations. Blood is no longer the default/assumed specimen
when a Change Request does not specify the specimen type. In the future, newly
added terms will include the specimen type if it is medically significant. When newterms without specimen type are added as PTs, any corresponding existing terms withspecimen type will be demoted to LLT and linked to this new term. As an example, LLT
Blood opiates increased is linked to PT Opiates positive.
For non-laboratory procedures (e.g., radiology), anatomic site replaces specimen typein the term and is stated in the text string.
It is important to consider the “incl” and “excl” aspects of any given term whennavigating through the hierarchy. For example, enzyme tests that are excluded from
HLGT Cardiac and vascular investigations (excl enzyme tests) and HLGT
Musculoskeletal and soft tissue investigations (excl enzyme tests) are found under
HLGT Enzyme investigations NEC. Reproductive system related hormone analyses arelocated under HLGT Endocrine investigations (incl sex hormones). Blood gas tests thatare excluded from HLGT Respiratory and pulmonary investigations (excl blood gases)
are grouped under HLGT Metabolic, nutritional and blood gas investigations.
Generally, the descriptors “direct” and “indirect” are used only at the LLT level; one
exception is the placement of Coombs direct/indirect tests at the PT level (e.g., PT
Coombs indirect test negative).
The “-gram” form of a term is considered a type of record of findings (e.g., PT
Audiogram) and is generally found at the PT level. The corresponding “-graphy” terms
are usually found as LLTs linked to their corresponding “-gram” terms (e.g., LLT Leftventriculography linked to PT Cardiac ventriculogram left).
6.13.3 Term Placement Guidelines (set forth in the first Blue Ribbon Panel in2003)
In most cases microbiology and serology investigations use general “serology” terms at
the LLT level. The same general rule applies to DNA tests. Specimen types are notdifferentiated at the PT level unless they have clinically different interpretations.
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Requested terms of antibody, IgG, IgM, of microorganisms are added at the LLT level
under a PT “genus + qualified or unqualified test” term.
Uncommon organisms have serology and DNA tests at the LLT level under a general
PT (e.g., LLT Babesia serology negative is linked to PT Parasitic blood test negative)..
For requested “culture” terms, only specimen terms of blood, CSF, urine, or stool forbacterial, fungal, and viral type investigations will remain at the PT level. Other
specimen terms will be represented at the LLT level. For example, LLT Culture bone
positive is linked to PT Culture positive.
The microorganism DNA tests (e.g. bacterial DNA test, viral DNA test positive, fungal
DNA test positive) are generally not represented at the PT level. They are represented
as LLTs under unqualified or test positive PTs such as LLT Bacterial DNA test positive
under PT Bacterial test positive , LLT Fungal DNA test positive under PT Fungal test
positive. The type of organism is also listed at the LLT level. For example, LLT
Pneumocystis carinii DNA test positive is linked to PT Pneumocystis test positive.
For hormone, mono- or oligosaccharides, amino acid, oligopeptides, or metal element
analysis, specimen types are not differentiated at the PT level unless they haveclinically different interpretations. Whether or not the specimen type will be represented
at the LLT level is determined by clinical significance.
For therapeutic drug monitoring analyses, there will be no further expansion of drugclasses at this time.
For narcotic drugs, specimen types are not differentiated at the PT level unless they
have clinically different interpretations.

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6.14 METABOLISM AND NUTRITION DISORDERS
6.14.1 Basis for Classification
There are three broad approaches to group terms at the HLGT level in this SOC. The
first type groups HLTs into HLGTs that describe disorders in the handling of specificsubstances by the body (e.g., HLGT Purine and pyrimidine metabolism disorders, HLGTInborn errors of metabolism, and HLGT Lipid metabolism disorders).
A second type of grouping assembles HLGTs describing conditions associated withnutritional disorders in general (e.g., HLGT Appetite and general nutritional disorders,
HLGT Vitamin related disorders).
The third type of HLGT covers medical conditions that may not be associated with a
specific metabolic or nutritional pathogenesis (e.g., HLGT Acid-base disorders, HLGTElectrolyte and fluid balance conditions).
6.14.2 Conventions and Exceptions
Due to the multiplicity of etiologies and effects of many imbalances and disorders, mostof these conditions have been assembled within HLT Metabolic disorders NEC under
HLGT Metabolism disorders NEC. It should be noted that there are two separate
HLGTs that relate to diabetes: HLGT Glucose metabolism disorders (incl diabetes
mellitus) and HLGT Diabetic complications.

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6.15 MUSCULOSKELETAL AND CONNECTIVE TISSUE DISORDERS
6.15.1 Basis for Classification
SOC Musculoskeletal and connective tissue disorders is classified at the HLGT level by
tissue type such as bone, muscle, and connective tissue or by disease entity such as
neoplasms, congenital disorders, and deformities. HLGT Musculoskeletal andconnective tissue disorders NEC is a general grouping category. Subordinate to this
HLGT, HLT Musculoskeletal and connective tissue conditions NEC categorizes terms
that are not classified elsewhere in this SOC.
Infection terms can be found in one of four HLGTs. Three of them include: HLT Boneand joint infections (excl arthritis) is linked to HLGT Bone disorders (excl congenital andfractures), HLT Infectious arthritis is linked to HLGT Joint disorders, and HLT Muscle
infections and inflammations is linked to HLGT Muscle disorders. In addition to thesethree HLTs, other infections in this SOC are grouped in HLT Musculoskeletal andconnective tissue infections and inflammations NEC under the general grouping HLGT
Musculoskeletal and connective tissue disorders NEC.
HLGT Musculoskeletal and connective tissue neoplasms has HLTs to categorize
neoplasms as benign, malignant, or either unspecified or premalignant.
6.15.2 Conventions and Exceptions
HLGT Fractures is closely aligned with HLGT Bone and joint injuries in SOC Injury,
poisoning and procedural complications. Terms that are directly attributed to trauma,
poisoning, and procedural complications are primarily linked to SOC Injury, poisoning
and procedural complications. For example, bone fractures, which in most cases are
attributed to trauma, are primary to SOC Injury, poisoning and procedural complications,whereas pathologic and osteoporotic fractures are primary to SOC Musculoskeletal andconnective tissue disorders.
HLT Soft tissue disorders NEC provides a grouping for those general soft tissue terms
that cannot be linked to other specific body system organ classes.

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6.16 NEOPLASMS BENIGN, MALIGNANT AND UNSPECIFIED(INCL CYSTS AND POLYPS)
6.16.1 Basis for Classification
This SOC is classified anatomically, with pathologic sub-classifications for staging ofboth benign and malignant neoplasms. The reference for PT names is the PDQ(Physicians Data Query) Terminology Guide, a publication of the United States National
Cancer Institute, except in the area of non-Hodgkin's lymphomas where the nosology
developed by the International Lymphoma Study Group [NL Harris, ES Jaffe, H Stein,
PM Banks, JK Chan, ML Cleary, G Delsol, C De Wolf- Peeters, B Falini, and KC Gatter.
A revised European-American classification of lymphoid neoplasms: a proposal from theInternational Lymphoma Study Group. Blood 1994, 84: 1361-1392] supersedes the
PDQ terminology. Several legacy classifications for lymphomas were incorporated into
LLTs.
Lymphoma classification in MedDRA at the PT level and above follows the Revised
European-American Lymphoma (R.E.A.L) Classification; the Working Formulation
classification is limited to the LLT level.
For cysts and polyps, the primary linkage is to the site of manifestation with secondary
linkage to SOC Neoplasms benign, malignant and unspecified (incl cysts and polyps).
All other neoplasm terms have a primary linkage to this SOC with secondary linkages tothe site of manifestation.
At the present time, the words “cancer” and “carcinoma” are used synonymously within
the anatomically classified HLGTs at the PT and LLT levels of the MedDRA hierarchy,
even though it is recognized that there is a distinction between such concepts. In
addition to the terms that relate to classifications by stage of therapy, there has been an
attempt to include PTs to capture terms that are less specific and do not provide staging
information (e.g., PT Breast cancer).
Breast neoplasms HLGTs make a distinction between male and female malignant
neoplasms. This is one of the few instances in MedDRA where a distinction is made forgender.
Primary site malignant neoplasms that have metastasized are qualified by the word
“metastatic” (e.g., PT Bone cancer metastatic represents a primary malignant neoplasmof bone which has metastasized to a site elsewhere in the body). Neoplastic lesions at
secondary sites are qualified by the phrase “metastases to” (e.g., PT Metastases togallbladder represents a malignant neoplasm from somewhere in the body that hasestablished a metastatic focus in the gallbladder).
6.16.2 Conventions and Exceptions
Terms that represent non-neoplastic conditions, that may be associated with neoplastic
conditions (e.g., PT Tumour ulceration) are found in HLT Oncologic complications andemergencies.
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Sarcomas are classified outside the strict anatomic classification due to the ubiquitous
nature of these neoplasms.
Malignant melanomas which do not specify an anatomical site, by convention areclassified as skin melanomas, which is the most prevalent location. For this reason, PT
Malignant melanoma links to HLT Skin melanomas (excl ocular). When staging for amalignant neoplasm is included in the text string, the naming convention of“site/malignancy/stage” is maintained as much as possible in this SOC.
Terms for staging information are not included for malignancies for which therapy is notstage-dependent.
HLGT Neoplasm related morbidities contains terms for disorders specifically related tooncologic complications and emergencies. Some, but not all, PTs in HLT Oncologic
complications and emergencies and HLT Paraneoplastic syndromes NEC that are
specific to sites of manifestation have primary links to that site with SOC Neoplasms
benign, malignant and unspecified (incl cysts and polyps) as a secondary link.
HLGT Metastases contains terms for both specific site involvement and unknown orunspecified sites. The specific site terms generally have a primary link to SOC
Neoplasms benign, malignant and unspecified (incl cysts and polyps) and a secondary
link to the site of manifestation SOC.
“Metastatic” terms (e.g., PT Ovarian cancer metastatic) are present at the PT level in
MedDRA and are distinct from other PTs indicating a “stage IV” of malignancy. Thishas been done because metastasis can occur at different stages of disease and is not
exclusively associated with stage IV, thus a linkage of “metastatic” terms to “stage IV”
terms would not always be appropriate.
“High” and “low” terms in MedDRA are generally considered to belaboratory/investigation type of terms and are found in SOC Investigations. An
exception to this rule is PTs representing “low grade” neoplasms which are linked to
SOC Neoplasms benign, malignant and unspecified (incl cysts and polyps) (e.g., PT
Astrocytoma, low grade).
The existing unqualified polyp terms in MedDRA (e.g. PT Gastric polyps) currently
default to a benign classification. Newly accepted polyp terms do not include a qualifierof “benign.” Polyps are secondarily linked to SOC Neoplasms benign, malignant andunspecified (incl cysts and polyps), and primarily linked to the appropriate site ofmanifestation SOC. Within SOC Neoplasms benign, malignant and unspecified (inclcysts and polyps), polyp terms are linked to HLTs that represent the benign form rather
than the malignant/unspecified form. Polyp terms with the qualifier of “malignant” will nolonger be added to MedDRA. Instead, it is recommended that subscribers use available“malignant neoplasm” terms for their coding needs.

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6.17 NERVOUS SYSTEM DISORDERS
6.17.1 Basis for Classification
Neurologic disorders are classified using three broad approaches at the HLGT level:
anatomic groupings, groupings based on etiology, and pathophysiologic groupings.
HLGTs containing disorders classified anatomically are represented by HLGT Spinal
cord and nerve root disorders and HLGT Cranial nerve disorders (excl neoplasms).
Examples of etiologic classification are HLGT Congenital and peripartum neurologicalconditions and HLGT Central nervous system infections and inflammations.
Pathophysiologic classification is exemplified by HLGT Demyelinating disorders and
HLGT Peripheral neuropathies.
In MedDRA, signs and symptoms uniquely associated with disorders are generally
included as HLGTs covering those disorders. However, neurologic signs andsymptoms that could be associated with a variety of disorders are classified under
HLGT Neurological disorders NEC, e.g., HLT Abnormal reflexes.
6.17.2 Conventions and Exceptions
HLT Optic nerve disorders NEC is included under HLGT Cranial nerve disorders (excl
neoplasms) rather than under HLGT Neurological disorders of the eye. HLT Pupillarysigns is included under HLGT Neurological disorders NEC.
Headaches have their own HLGT and are not included under HLGT Neurologicaldisorders NEC.
HLT Hereditary muscle disorders is linked to HLGT Congenital and peripartum
neurological conditions rather than to HLGT Neuromuscular disorders.
HLT Coma states is linked to HLGT Neurological disorders NEC.

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6.18 PREGNANCY, PUERPERIUM AND PERINATAL CONDITIONS
6.18.1 Basis for Classification
Disorders are grouped in a variety of ways in this SOC to distinguish between maternal,
fetal, and neonatal disorders, and to delineate disorders according to the timeline ofpregnancy (e.g., labor, delivery, postpartum, etc.). Examples of this type are HLGTMaternal complications of labour and delivery and HLGT Postpartum and puerperal
disorders. Others are classified at the HLGT level according to anatomy (e.g., HLGT
Placental, amniotic and cavity disorders (excl haemorrhages)). Other HLGTs areclassified to differentiate maternal and fetal disorders (e.g., HLGT Foetal complicationsand HLGT Maternal complications of pregnancy).
6.18.2 Conventions and Exceptions
This SOC includes terms that represent both normal and high-risk conditions related topregnancy that are not complications or adverse events (e.g., PT Twin pregnancy or PT
Elderly primigravida). These are classified in HLGT Pregnancy, labour, delivery andpostpartum conditions.
Abnormalities of fetal presentation, which could be considered both a maternal and fetal
complication, have been classified under HLGT Foetal complications in HLT Foetal
position and presentation abnormalities.
HLGT Neonatal and perinatal conditions represents the only specific “pediatric”
grouping within the terminology. Terms for other pediatric conditions are dispersed
amid terms for adult conditions.
Terms relating to fetal and neonatal issues are generally primarily linked to the site ofmanifestation SOC with a secondary link to this SOC. Terms involving fetal exposure to
drugs and other substances (e.g., tobacco) have a primary link to SOC Injury, poisoning
and procedural complications and a secondary link to SOC Pregnancy, puerperium andperinatal conditions.
For terms related to “abortion,” the following are points of note: Both “spontaneous” and “not specified” abortions are single-axial terms linked to
SOC Pregnancy, puerperium and perinatal conditions.

 All “induced” forms of abortion are linked only to SOC Surgical and medical
procedures.

 Complications of induced abortion are primarily linked to HLT Induced abortion
complications (under HLGT Procedural related injuries and complications NEC in
SOC Injury, poisoning and procedural complications).

 Complications of both “spontaneous” and “not specified” abortions are primarily
linked to HLT Abortion related conditions and complications (under HLGTAbortions and stillbirth in SOC Pregnancy, puerperium and perinatal conditions).

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When searching for terms describing toxic exposures related to pregnancy, delivery,
lactation and other circumstances potentially impacting the fetus or newborn, the user
may need to consider selected PTs in certain HLTs in this SOC (including, but possibly
not limited to, HLT Foetal conditions due to maternal conditions and HLT Newborn
complications NEC) as well as various “exposure” concepts located in SOC Injury,
poisoning and procedural complications (e.g., terms linked to HLGT Exposures,chemical injuries and poisoning).
“Perineum” terms may be linked to several SOCs including SOC Reproductive systemand breast disorders and SOC Pregnancy, puerperium and perinatal conditions. New“perineum” terms resulting from Change Requests are linked to their most appropriateclassification on a case-by-case basis.
Most “death” terms are linked primarily to SOC General disorders and administrationsite conditions. Fetal and maternal death terms are linked primarily to SOC Pregnancy,
puerperium and perinatal conditions as they are considered a special population.
However, PT Death neonatal is linked primarily to SOC General disorders andadministration site conditions and secondarily to SOC Pregnancy, puerperium andperinatal conditions.

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6.19 PRODUCT ISSUES
6.19.1 Basis for Classification
The MedDRA Management Committee endorsed the recommendation of the Blue
Ribbon Panel on the scope of MedDRA (April 2014) for the addition of a 27th SOC to
MedDRA to accommodate non-clinical/non-patient related concepts pertaining to
products. These concepts are important from regulatory and public health perspectives
as they may affect patient safety. This SOC Product issues has been added in MedDRA
Version 19.0 and includes terms relevant for issues with product quality, devices,manufacturing quality systems, product supply and distribution, and counterfeit
products. One of the goals of incorporating product quality terms into MedDRA is tosupport the recording of product quality issues and any associated adverse eventsusing a single terminology. It is envisaged that the product quality terms, including thoserelating to manufacturing and distribution, may be used to report product defects toregulatory authorities and may also be used in organizations' internal databases to track
and trend quality issues or deviations.
SOC Product issues contains two HLGTs: HLGT Device issues and HLGT Productquality, supply, distribution, manufacturing and quality system issues. HLGT Device
issues has been moved from SOC General disorders and administration site conditions
with all its eight subordinate HLTs (HLT Device computer issues, HLT Device electricalissues, HLT Device incompatibility issues, HLT Device information output issues, HLT
Device issues NEC, HLT Device malfunction events NEC, HLT Device operational
issues NEC, and HLT Device physical property and chemical issues).
HLGT Product quality, supply, distribution, manufacturing and quality system issues
contains five product quality HLTs which have been moved from SOC Generaldisorders and administration site conditions (HLT Product contamination and sterility
issues, HLT Product label issues, HLT Product packaging issues, HLT Product physicalissues, and HLT Product quality issues NEC). In addition, this HLGT contains eight
HLTs which have been added in MedDRA Version 19.0 to cover issues relating tocounterfeit products, manufacturing quality, and supply and distribution: HLTCounterfeit, falsified and substandard products, HLT Manufacturing facilities andequipment issues, HLT Manufacturing issues NEC, HLT Manufacturing laboratory
controls issues, HLT Manufacturing materials issues, HLT Manufacturing production
issues, HLT Product distribution and storage issues, and HLT Product supply andavailability issues.
6.19.2 Conventions and Exceptions
This SOC is focused on issues related to products rather than clinical or patient related
concepts and, therefore, the majority of terms are single-axial and have no need for
multi-axial links to other patient related “disorder” SOCs. However, product terms that
also denote a patient related issue express multi-axiality to preserve the link to patient
safety. For example, PT Transmission of an infectious agent via product is linked to
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primary SOC Infections and infestations and has a secondary link to SOC Productissues.
Device terms are generally event based, not device type based. However, MedDRA has
evolved in response to users' requests to add certain device type terms when thesedevices are widely used or have a particular clinical relevance. Therefore, exceptions
have been made for generic types of devices and device components (in widespreaduse) such as stents, pumps, needles, and syringes. In general, medical device event
concepts are represented at the PT level, while corresponding sub-concepts pertaining
to events with specific types of widely used devices are usually represented at the LLTlevel.
HLT Manufacturing laboratory controls issues is intended to cover issues with various
laboratory tests conducted during the manufacturing process, including stability testing.
HLT Product distribution and storage issues is intended to cover issues with the storageof products by manufacturers, distributors, wholesalers, etc. In contrast, product storage
issues by end-users such as healthcare professionals, patients, and consumers are
considered to be medication errors and are represented by appropriate medication error
terms in SOC Injury, poisoning and procedural complications.
HLT Product supply and availability issues is distinct from distribution, shipping andstorage concepts and is intended to cover concepts such as supply chain interruption,
product not available on formulary, product withdrawn from market, etc.

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6.20 PSYCHIATRIC DISORDERS
6.20.1 Basis for Classification
The primary guideline used for the classification of psychiatric disorders is the
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, (DSM-5)
published by the American Psychiatric Association. Associated symptoms are groupedat the HLGT levels according to the classification scheme suggested by the DSM-5.
The disorders specifically named by DSM5, or those in the vocabulary that are very
closely related disorders, are placed together in the appropriate HLT. Signs andsymptoms uniquely associated with disorders under an HLGT are grouped at the HLTlevel. For example, HLGT Depressed mood disorders and disturbances includes an
HLT for the DSM-5 listed Depressive disorders, and another HLT for HLT Moodalterations with depressive symptoms, which includes the depression-related symptoms
which would not meet the DSM-5 criteria for a diagnosis.
For MedDRA Version 19.0, HLGT Somatoform and factitious disorders was replacedwith new HLGT Somatic symptom and related disorders. Similarly, HLT Somatoform
disorders, HLT Mental retardations and HLT Paraphilias were also replaced by HLTSomatic symptom disorders, HLT Intellectual disabilities and HLT Paraphilias andparaphilic disorders respectively due to changes in how these concepts are referenced
in DSM-5.
Signs and symptoms that are applicable to multiple DSM-5 classifications are grouped
under the general HLGT Mood disorders and disturbances NEC and HLGT Psychiatricand behavioural symptoms NEC.
Terms that have a basis in a central nervous system disorder are linked primarily to
SOC Nervous system disorders and secondarily to SOC Psychiatric disorders. For
example, PT Dementia Alzheimer's type has a primary link to SOC Nervous systemdisorders and a secondary link to SOC Psychiatric disorders.
Congenital disorders such as PT Tourette's disorder that have a basis in SOC
Psychiatric disorders have a primary link to SOC Congenital, familial and genetic
disorders in accordance with MedDRA rules. These terms have secondary links to
SOC Psychiatric disorders, as well as to the body system of manifestation.
HLGT Sleep disorders and disturbances includes HLTs that cover all aspects of sleep
disorders. HLT Parasomnias contains abnormal sleep-related disturbances (e.g., PT
Abnormal dreams, PT Nightmare, and PT Somnambulism).
Conditions associated with substance abuse (e.g., LLT Enema abuse, LLT Laxative
abuse under PT Drug abuse, and PT Alcoholism) are included in SOC Psychiatricdisorders in HLT Substance related and addictive disorders.
According to DSM-5, the official psychiatric term for addiction is “substancedependence.” Therefore, the word “addiction,” in general, only appears at the LLT levelin MedDRA.

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For new “abuse” terms in MedDRA, the text string is devised to distinguish terms in
SOC Social circumstances from those in SOC Psychiatric disorders. “Abuse” terms arelinked to SOC Psychiatric disorders and kept independent of “dependence” counterpart
PTs. Terms that refer to a person, such as PT Drug abuser, are in SOC Social
circumstances.
6.20.2 Conventions and Exceptions
An attempt is made to name disorders that are included in DSM-5 using the conventions
established by the American Psychiatric Association. However, these disorders areassociated with a specific set of criteria for diagnosis, while the more general names inthe existing vocabulary do not always map in a one-to-one manner. For this reason,
they are all included as disorders under the same HLT.

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6.21 RENAL AND URINARY DISORDERS
6.21.1 Basis for Classification
The majority of HLGTs in this SOC are based on anatomic classification (e.g., HLGT
Bladder and bladder neck disorders (excl calculi) and HLGT Ureteric disorders).
Further subdivision on the HLT level has PTs grouped by disease process wherever
possible (e.g., HLT Bladder infections and inflammations, HLT Bladder reflux
conditions), and those remaining are grouped under HLTs such as HLT Bladderdisorders NEC.
HLGT Genitourinary tract disorders NEC contains terms that do not specify exact sites
within the genitourinary tract. Within this HLGT, HLTs are subdivided into congenital,
infectious and inflammatory, and miscellaneous categories. Where a site is specified,
the terms for neoplasms and congenital disorders are gathered at the HLT level within
the HLGT of the appropriate anatomic site (e.g., HLT Renal neoplasms in HLGT Renal
disorders (excl nephropathies) and HLT Ureteric disorders congenital within HLGT
Ureteric disorders).
Signs and symptoms in this SOC are grouped under HLGT Urinary tract signs andsymptoms, which has three HLTs: HLT Bladder and urethral symptoms, HLT Urinary
abnormalities, and HLT Urinary tract signs and symptoms NEC.
6.21.2 Conventions and Exceptions
HLT Urinary abnormalities gathers most of the “-uria” terms present in the terminology.
This decision was made to avoid conflicts with respect to underlying etiology as in thecase of PT Proteinuria, which may have several intrarenal and extrarenal etiologies
The corresponding terms with the phrase or concept “in urine” (e.g., PT Protein urinepresent) are found in SOC Investigations.
For the major body systems of cardiac, hepatic, pulmonary, and renal, the terms“failure” and “insufficiency” are used synonymously. In SOC Renal and urinary
disorders, the “failure” term is at the PT level and the “insufficiency” term is at the LLTlevel (e.g., PT Renal failure and LLT Renal insufficiency).

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6.22

REPRODUCTIVE SYSTEM AND BREAST DISORDERS

6.22.1 Basis for Classification
The terms within this SOC are classified using two general approaches: anatomic andfunctional.
HLGTs based on anatomy (e.g., HLGT Breast disorders and HLGT Penile and scrotal
disorders (excl infections and inflammations)) are subdivided mainly by disease process
at the HLT level (e.g., HLT Benign and malignant breast neoplasms, HLT Lactation
disorders). Signs and symptoms for the anatomic part may form an HLT (e.g., HLT
Prostatic signs, symptoms and disorders NEC and HLT Breast signs and symptoms).
Other HLGTs reflect functional disorders e.g., HLGT Sexual function and fertility
disorders and HLGT Menopause related conditions. HLTs are based on subtypes offunctional disorder (e.g., HLT Erection and ejaculation conditions and disorders, HLT
Spermatogenesis and semen disorders).
HLGT Congenital reproductive tract and breast disorders contains terms for conditions
present at birth irrespective of whether the conditions are hereditary or acquired inutero. The HLTs allocate terms on the basis of gender (male, female, or unspecified).
Infections and inflammations are not linked to the HLGTs by anatomic location but bygender (e.g., HLGT Female reproductive tract infections and inflammations and HLGTMale reproductive tract infections and inflammations). Terms where gender is not
specified are in HLT Reproductive tract infections and inflammations NEC within HLGT
Reproductive tract disorders NEC.
HLGT Reproductive tract disorders NEC provides a broad classification for terms where
gender is not specified. The HLTs include HLT Gender disorders and HLT
Reproductive tract disorders NEC (excl neoplasms) as well as terms for neoplasms,
infections and inflammations, and signs and symptoms.
6.22.2 Conventions and Exceptions
Unlike other anatomically based HLGTs in this SOC, which exclude terms for infections
and inflammations, HLGT Breast disorders contains HLT Breast infections andinflammations.
“Perineum” terms may be linked to several SOCs including SOC Reproductive systemand breast disorders and SOC Pregnancy, puerperium and perinatal conditions. New“perineum” terms resulting from Change Requests are linked to their most appropriateclassification on a case-by-case basis.
For historical and practical reasons the MSSO prefers to keep the unqualified concepts
for intraepithelial lesions such as LLT High grade squamous intraepithelial lesion under
PT Cervical dysplasia. For areas other than cervix, the MSSO provides corresponding
intraepithelial concepts upon request under the appropriate PTs such as LLT Low
grade prostatic intraepithelial neoplasia under PT Prostatic dysplasia or LLT Anal highgrade squamous intraepithelial lesion under PT Anogenital dysplasia.
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6.23 RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS
6.23.1 Basis for Classification
HLGTs that reflect the anatomic site (e.g., HLGT Pleural disorders) contain HLTs basedon pathologic classification (e.g., HLT Pleural infections and inflammations, HLT
Pneumothorax and pleural effusions NEC). HLGTs that describe a larger anatomic site
(e.g., HLGT Upper respiratory tract disorders (excl infections)) are further divided at the
HLT level into more specific anatomic locations, disease processes, or a combination ofparameters (e.g., HLT Nasal congestion and inflammations). Other HLGTs are basedon disease processes (e.g., HLGT Respiratory tract neoplasms) with anatomic
subdivisions as HLTs.
HLGTs may also reflect both the anatomic site and disease process (e.g., HLGT Lower
respiratory tract disorders (excl obstruction and infection) and HLGT Upper respiratory
tract disorders (excl infections)).
HLGT Respiratory tract infections contains HLTs based on infective organisms(bacterial, viral, etc.), as well as anatomic site groupings (e.g., HLT Upper respiratory
tract infections NEC).
Specific HLGTs have been created for congenital disorders (HLGT Congenital
respiratory tract disorders), neonates (HLGT Neonatal respiratory disorders), andrespiratory disorders (HLGT Respiratory disorders NEC) which contain HLTs that are
not based on anatomic sites or specific disease processes (e.g., HLT Breathingabnormalities).
6.23.2 Conventions and Exceptions
The title of HLGT Lower respiratory tract disorders (excl obstruction and infection) is
self-explanatory. Infections are in a separate HLGT, but obstruction terms reside in
HLT Bronchospasm and obstruction within HLGT Bronchial disorders (excl neoplasms).
HLGT Upper respiratory tract disorders (excl infections) is not similarly structured.
Although infections are excluded in a separate HLGT, terms for obstruction may residewithin the same HLGT Upper respiratory tract disorders (excl infections). These PTs
are in the HLTs for the appropriate anatomic site (e.g., PT Nasal dryness is within HLTNasal disorders NEC). Terms describing obstructions may also be in other HLGTsplaced by causal factors. For instance, PT Tracheitis obstructive is linked to HLT Upper
respiratory tract infections NEC within HLGT Respiratory tract infections.
Infections have been placed in a single HLGT, namely, HLGT Respiratory tract
infections. However, HLT Pleural infections and inflammations is in HLGT Pleuraldisorders.
All neoplasms are within HLGT Respiratory tract neoplasms with the exception of
pleural neoplasms, which are in HLGT Pleural disorders (HLT Pleural neoplasms).

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PT Sputum decreased and PT Sputum increased are in SOC Respiratory, thoracic andmediastinal disorders. This is because these terms commonly express a medical
condition rather than an investigation finding.
For the major body systems of cardiac, hepatic, pulmonary, and renal, the terms“failure” and “insufficiency” are used synonymously. In SOC Respiratory, thoracic andmediastinal disorders, the “failure” term is at the PT level and the “insufficiency” term isat the LLT level (e.g., PT Respiratory failure and LLT Respiratory insufficiency).

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6.24 SKIN AND SUBCUTANEOUS TISSUE DISORDERS
6.24.1 Basis for Classification
The principal division at the HLGT level in this SOC is by pathophysiology or etiology(e.g., HLGT Angioedema and urticaria, HLGT Pigmentation disorders, and HLGT
Cutaneous neoplasms benign). The exceptions are HLGT Skin appendage conditions,which is a microanatomic grouping, and HLGT Epidermal and dermal conditions, whichgroups skin conditions that do not belong to any of the other HLGTs. At the HLT level,
the division is mainly pathologic.
6.24.2 Conventions and Exceptions
In general, terms related to the eyelid are primarily linked to SOC Eye disorders andsecondarily to SOC Skin and subcutaneous tissue disorders.

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6.25 SOCIAL CIRCUMSTANCES
6.25.1 Basis for Classification
SOC Social circumstances is one of the three single-axial SOCs in MedDRA. The
purpose of this SOC is to provide a grouping for those factors that may give insight into
personal issues that could have an effect on the event being reported. Essentially, SOC
Social circumstances contains information about the person, not the adverse event. As
an example, terms such as PT Drug abuser and PT Death of relative are found in this
SOC, whereas their respective disorder terms such as PT Drug abuse and PT Deathare found in SOC Psychiatric disorders and SOC General disorders and administrationsite conditions, respectively.
The terms within this SOC do not fall into any anatomic or pathologic classification. The
HLGTs are broad groupings of social factors (e.g., family issues, legal issues, or
economic circumstances). At the HLT level, these HLGTs are further subdivided into
groups of social factors with a common theme (e.g., HLGT Family issues is divided into
HLT Bereavement issues, HLT Dependents, and HLT Family and partner issues).
In MedDRA, terms representing crime or action of abuse and the perpetrator of thecrime or abuse are kept in a PT/LLT relationship, with crime/action of abuse at the PT
level and perpetrator of the crime or abuse at the LLT level under HLT Criminal activity
in SOC Social circumstances (e.g., PT Sexual abuse and its LLT Sexual abuser).
Terms representing the victim of these crimes are qualified with "victim of" at the PT
level under HLT Crime victims in SOC Social circumstances. Unqualified terms
representing the victim are placed under the "victim of" PT as an LLT ( e.g., PT Victim
of child abuse and LLT Maltreated child).
For new “abuse” terms in MedDRA, the text string is devised to distinguish terms in
SOC Social circumstances from those in SOC Psychiatric disorders. "Abuse" terms arelinked to SOC Psychiatric disorders and kept independent of “dependence” counterpart
PTs. Terms that refer to a person, such as PT Drug abuser, are in SOC Social
circumstances.
6.25.2 Conventions and Exceptions
HLT Drug and chemical abuse excludes alcohol-related terms. HLT Alcohol productuse captures all aspects, including alcoholic, abstention, and social use. PT Alcoholism
is found in SOC Psychiatric disorders.
HLGT Legal issues makes a distinction between being a victim of a crime and being theperson who committed the crime.

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PT Blindness is linked to HLGT Vision disorders. To make a distinction between
blindness as a disability and blindness as a medical disorder, PT Sight disability islinked to SOC Social circumstances (blindness as a disability) and PT Blindness islinked to SOC Eye disorders (blindness as a medical disorder) and to SOC Nervous
system disorders. Similar terms relate to deafness (i.e., PT Deafness is in SOC Ear
and labyrinth disorders and PT Hearing disability is in SOC Social circumstances).

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6.26 SURGICAL AND MEDICAL PROCEDURES
6.26.1 Basis for Classification
This SOC is one of the three single-axial SOCs in MedDRA. It contains only thoseterms that are surgical or medical procedures. There are no multi-axial links between
terms in this SOC and other SOCs.
The nature of this SOC makes it more of a “support” SOC for recording case informationand for developing queries. Surgical and medical procedures may occur in thetreatment of an adverse event, as an associated condition related to the indication for a
medical product, or as medical history. A comprehensive search strategy needs toconsider that this is a single-axial SOC whose terms are not found elsewhere in theterminology.
The terms within this SOC are primarily divided by anatomic region at the HLGT level,with the exception of HLGT Therapeutic procedures and supportive care NEC. This
HLGT groups general or miscellaneous therapeutic procedures, and HLGT Soft tissue
therapeutic procedures, groups subordinated HLTs by tissue type.
There is a distinction between the term “abortion,” which is frequently used as aprocedure term, and a disorder term such as “spontaneous abortion.” In MedDRA, theterm “induced abortion” is used to identify the term as a procedure; therefore, it is in thisSOC. The term “spontaneous abortion” is used as the disorder term and is in SOC
Pregnancy, puerperium and perinatal conditions. When an abortion term is not
identified as being either a procedure or a disorder, it is assumed to be a disorder term
and is categorized in SOC Pregnancy, puerperium and perinatal conditions.
6.26.2 Conventions and Exceptions
The anatomic breakdown at HLGT level is similar to the SOC organization (represented
body systems) in MedDRA, with a few exceptions where treatment of certain bodysystems are closely related. The result is groupings that are similar to surgicalsubspecialties:

 Ear, nose, and throat procedures are grouped under a single HLGT, HLGT Headand neck therapeutic procedures, since procedures in these areas constitute asingle surgical speciality.

 Skull and vertebrae procedures are grouped with brain and spinal cord therapy.
 Muscle, tendon, cartilage fascia, and bursa operations are grouped in HLGT Softtissue therapeutic procedures. However, PT Ligament operation is linked to HLTJoint therapeutic procedures in HLGT Bone and joint therapeutic procedures.
At the PT and LLT level, terms with the words “operation” and “surgery” are usedinterchangeably.
Standard medical definitions of "dilation” and "dilatation" indicate that they aresynonyms. The MSSO recognizes that there are some common usages in certain
cultures for these types of terms. However, for purposes of distinction in MedDRA, the
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term "dilation" is considered a procedure and the term "dilatation" is considered adisorder. The word "procedure" is normally added to "dilation," e.g., PT Stomach dilation
procedure to make it self explanatory. An exception to this convention is PT Uterine
dilation and curettage since it is recognized as a procedure without the addition of thequalifying word.
Anastomosis is classified as a surgical procedure and is single-axial linked to SOC
Surgical and medical procedures. Alternative terms are used to describe relateddisorders outside of the surgical realm.
"Drainage" is a term used as a procedure (systematic withdrawal of fluids), whereas"discharge" and "secretion" are terms used for the excretion of liquids from the body.
"Drainage" terms that fall outside of the realm of surgical procedures are considered
exceptions and dealt with by using the word "discharge." These terms are linked
appropriately based on their particular meaning (e.g., PT Post procedural discharge
links to SOC Injury, poisoning and procedural complications). In addition, all surgicalterms retain "drainage" and link to SOC Surgical and medical procedures. Finally, if aterm can be either a surgical procedure or a non-surgical term, then both the"term+drainage" (PT Post procedural drainage linked to SOC Surgical and medical
procedures) and the "term+discharge" (PT Post procedural discharge linked to SOC
Injury, poisoning and procedural complications) are present in the terminology andlinked as indicated above. The MSSO recognizes that there are some common usages
in certain cultures for these types of terms that may not be reflected by this MedDRA
rule. Subscribers are advised to make clear which concept applies - surgical, nonsurgical, or both - when submitting Change Requests.
Revision procedures are generally represented in MedDRA as sub-concept LLTs of thebasic procedure concept for example LLT Ileostomy revision is placed under PT
Ileostomy and LLT Amputation revision placed under PT Amputation.

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6.27 VASCULAR DISORDERS
6.27.1 Basis for Classification
The terms within this SOC are primarily divided by pathology or clinical disease entity at
the HLGT level. Most vascular disorder terms are already grouped anatomically by theirrepresentation within the anatomic “disorder” SOCs; this division allows more flexible
data retrieval. At the HLT level, terms are further subdivided anatomically. Although
not identical, there is a close similarity in the distribution of anatomic locations
represented at the HLT level under HLGT Arteriosclerosis, stenosis, vascularinsufficiency and necrosis, HLGT Embolism and thrombosis, HLGT Vascular disorders
NEC, and HLGT Vascular haemorrhagic disorders.
6.27.2 Conventions and Exceptions
In general, terms related to thrombosis are primarily linked to the site of manifestation,
when applicable, and are secondarily linked to SOC Vascular disorders.
Conditions represented in HLGT Arteriosclerosis, stenosis, vascular insufficiency andnecrosis, and in HLGT Embolism and thrombosis are closely related in clinical orpractical view. However, whereas the first one addresses “chronic” impairments
developed progressively (such as PT Renal arteriosclerosis), the second one
represents “acute” conditions (e.g., LLT Renal artery embolism or PT Renal artery
thrombosis compared to PT Renal artery stenosis or PT Renal artery arteriosclerosis).
“High” and “low” terms in MedDRA are generally considered to belaboratory/investigation type of terms and are found in SOC Investigations. Exceptions
to this rule are LLT Blood pressure high and LLT Low blood pressure under PT
Hypertension and PT Hypotension, respectively, which are in SOC Vascular disorders.

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APPENDIX A: ACRONYMS
A
ASCIIAmerican Standard Code for Information InterchangeC
CIOMS
COSTART

Council for International Organizations of Medical Sciences
Coding Symbols for a Thesaurus of Adverse Reaction Terms

E
EWG
EXCL

Expert Working Group
Excluding, except, excl

F
FDA

Food and Drug Administration (United States)

H
HARTS
HLGT
HLT

Hoechst Adverse Reaction Terminology System
High Level Group Term
High Level Term

I
ICD-9
ICD-9-CM
ICH
IFCC
IFPMA
INCL
IUPAC

International Classification of Diseases – 9th RevisionInternational Classification of diseases – 9th Revision
Clinical Modification
International Council for Harmonisation of Technical Requirements for
Pharmaceuticals for Human Use
International Federation of Clinical Chemistry and Laboratory Medicine
International Federation of Pharmaceutical Manufacturers and Associations
Including, incl
International Union of Pure and Applied Chemistry

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J
J-ART
JPMA

Japanese Adverse Reaction Terminology
Japan Pharmaceutical Manufacturer Association

L
LLT
LOINC

Lowest Level Term
Logical Observation, Identifiers, Names and Codes

M
MCA
MEDIS
MedDRAMEDDRA
MHLW
MHRA
MSSO

Medicines Control Agency (United Kingdom)
Medical Information System (Japan)
Medical Dictionary for Regulatory Activities
Medical Dictionary for Drug Regulatory Affairs
Ministry of Health, Labour and Welfare (Japan)
Medicines and Healthcare products Regulatory Agency (United Kingdom)
Maintenance and Support Services Organization

P
PT

Preferred Term

S
SMQ
SOC

Standardised MedDRA Query
System Organ ClassW
WHO
WHO-ART

World Health Organization
World Health Organization Adverse Reaction Terminology

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For a list of MedDRA term abbreviations and acronyms, please visit our Web site(http://www.meddra.org/how-to-use/support-documentation).

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Appendix B: MedDRA Concept Descriptions

APPENDIX B: MedDRA CONCEPT DESCRIPTIONSThis appendix provides a list of MedDRA concept descriptions. A concept description isa description of how a concept is interpreted, used, and classified within the MedDRA
terminology and is not a definition. The concept descriptions are intended to aid theconsistent and accurate use of MedDRA in coding, retrieval, and analysis and to
overcome the differences of medicine practice worldwide. The MSSO expects thisappendix to be a working document and grow as subscribers request additional
concepts to be documented.
ABCDEFGHIJKLMNOPQRSTUVWXYZ

AAbuse
For the purposes of term selection and analysis of MedDRA-coded data,abuse is the intentional, non-therapeutic use by a patient or consumer of a
product – over-the counter or prescription – for a perceived reward ordesired non-therapeutic effect including, but not limited to, “gettinghigh”(euphoria). Abuse may occur with a single use, sporadic use or
persistent use of the product.
Acute
For use in medicine, the word means “reaching a crisis rapidly.” In someinstances, an “acute” condition may be interpreted as more severe than a“chronic” one. This was considered during the processing of proposed
modified terms to assure that terms expressing only severity were notincluded.
Addiction
For the purposes of term selection and analysis of MedDRA-coded data,
addiction is an overwhelming desire by a patient or consumer to take adrug for non-therapeutic purposes together with inability to control or stop
its use despite harmful consequences. Addiction can occur because drug
induces physical dependence and consequently a withdrawal syndrome,
but this is not an essential feature; and addiction can occur because of adesire to experience the drug's psychological, behavioral or physicaleffects.
AggravatedFrom “aggravate”: To make worse, e.g., “bronchitis aggravated bysmoking.” For the purposes of term placement in MedDRA, the use ofmodifiers exacerbated, aggravated and worsened is interchangeable
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Application site
For the purposes of MedDRA, an application site is considered to be thesurface that contacts a topical medication in the form of a cream, lotion, or
patch (e.g., an estrogen hormone patch). It does not pertain to othermethods of drug delivery such as injection or infusion by catheter or othermeans.
Angina“Angina” exists in MedDRA as a non current LLT because of theambiguous nature of the term. Angina is interpreted as a variant
expression for acute tonsillitis (angina tonsillaris) in certain languages.
However, based on the popular usage of this term in English language forAngina pectoris, in MedDRA it is linked to PT Angina pectoris.
Arthritis/Arthrosis
In MedDRA, any inflammation of a joint is considered “arthritis.” In
contrast “arthrosis” is interpreted as a non-inflammatory degenerative joint
disease and is linked to PT Osteoarthritis.
C
Cancer/Carcinoma"Cancer" is a disease in which abnormal cells divide uncontrollably andcan spread to other parts of the body (metastasize). "Cancer" can be oneof several histologic types including those derived from epithelial tissues(carcinomas), those derived from mesenchymal tissue (sarcomas), andthose arising from hematopoietic and lymphoid tissues (leukemia,
lymphomas, and multiple myeloma). In the context of MedDRA,"carcinoma" and "cancer" are considered synonymous. “Carcinoma" terms
are generally subordinate to "cancer" terms (e.g., LLT Skin carcinoma islinked to PT Skin cancer).
Cell marker
A cell marker is a biochemical or genetic characteristic of a cell which
discriminates between different cell types.
Chronic
Of long duration; subject to a disease or habit for a long time. In someinstances, a “chronic” condition may be interpreted as milder than an“acute” one. This was considered during the processing of proposed
modified terms to assure that terms expressing only severity were notincluded.
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ClosureClosure is the cap, lid, stopper or other feature which is the primarymechanism for protecting the product from spill, air etc.
Cold
For purposes of MedDRA, the mention of “cold” without addition of any
prefix of feeling signifies the catarrhal disorder associated withnasopharyngitis. “Coldness” and “feeling cold,” are body temperature
perceptions of uncomfortably low temperature for humans.
Compounding
Compounding refers to products that are usually made by a pharmacist or
physician.
Compounding issue
Compounding issue refers to quality problems associated with those
products.
CoringA small piece of the stopper is sometimes sheared off (known as coring);
an example could be after a needle is inserted through the stopper of a
medication vial.
Crystal formation
Crystals are symmetrically arranged formations created by thesolidification of a chemical element, a compound, or a mixture found in oron the dosage form which is not normal for the product.
D
Device capture
PT Device capturing issue refers to a situation where a device fails
capture signal input or output, or captures the wrong signal input or output.
Device use error
An act or omission of an act that results in a different medical device
response than intended by the manufacturer or expected by the operator.
Diaphragm
For purposes of MedDRA, diaphragm is considered a respiratory
structure.
Dispensing Error
Dispensing errors are not limited to pharmacists. It can include nurses
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and physicians. For example, physicians can dispense sample productsin their office.
Dissolution
Dissolution is the process in which one substance is dissolved in another.
Dissolution and solubility are considered synonyms in MedDRA.
DosageThe determination and regulation of the size, frequency, and number ofdoses.
Dosage Form
The physical form in which a drug is produced for administration torecipient (tablets, capsules, cream etc.).
Dose
A quantity to be administered at one time, such as a specified amount of
medication.
Dose Omission
The failure to administer an ordered dose to a patient before the nextscheduled dose, if any. This excludes patients who refuse to take a
medication, a clinical decision (e.g., contraindication), or other reasons not
to administer (e.g., patient sent for test).

Documented hypersensitivity to administered drug
This medication error refers to the situation when a patient is administereda drug that is documented in the patient's medical file to cause a
hypersensitivity reaction in the patient. Example: Despite the fact that thepatient's medical record indicated "sulfa allergy," the physician prescribeda sulfa antibiotic. Subsequently, the patient took the antibiotic andexperienced hives. A related term, PT Documented hypersensitivity toadministered product, applies to similar situations involving known
hypersensitivity to other types of products, not specifically drugs.
Drug diversion
For the purposes of term selection and analysis of MedDRA-coded data,
drug diversion means that a drug is diverted from legal and medicallynecessary uses toward illegal uses.
Drug Formulation
Refers to both active and inactive ingredients.
Duration
Includes duration of therapy/length of therapy.
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E
Exacerbation
See “Aggravated.” For the purposes of term placement in MedDRA, theuse of modifiers exacerbated, aggravated and worsened isinterchangeable
Exposure
For the purposes of MedDRA, the concept of “exposure”:
 Is not limited to drugs; it can include exposure to chemicals, toxins,
radiation, communicable disease, etc.
 Can occur through various pathways (via blood, direct contact, etc.)
Extension
When paired with a product or a device, an extension is a component of adevice that carries the impulses from the implant site of a device to thelead.
GGel Formation
A product has formed into a gelatinous matter, a colloid in a more solid
form than a solution which is not normal for the product.
HHigh Blood Pressure“High” and “low” terms in MedDRA are generally considered to belaboratory/investigation type of terms and are found in the SOC
Investigations. However, because of the synonymous use of expression
blood pressure high and hypertension in common usage, the LLT Bloodpressure high is linked to PT Hypertension in SOC Vascular disorders.
Hypertension vs. Hypertonia
Hypertonia” may be synonymous for “hypertension” in some languages.
However, for purposes of MedDRA, hypertonia is defined as a condition
marked by an abnormal increase in muscle tension and a reduced abilityof a muscle to stretch. Hence, it is placed in muscle tone disorders.
Hy's Law
Hy's law is used as an indicator for potential drug-induced liver injury. To
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be considered a potential “Hy's law” case, the following three components
must all be met: Elevation of aminotransferases, e.g., alanine aminotransferase(ALT) and aspartate aminotransferase (AST), of >3x upper limit
of normal (ULN)
 Alkaline phosphatase (ALP) <2x ULN
 Increase in total bilirubin ≥2x ULN
Please refer to the July 2009 FDA Guidance for Industry – “Drug-Induced
Liver Injury: Premarketing Clinical Evaluation” for additional information.
I
Inappropriate Schedule
Includes all deviations from the prescribed dosage schedule.
Intercepted medication error
For the purposes of term selection and analysis of MedDRA-coded data,
an intercepted medication error refers to the situation where a medication
error has occurred, but is prevented from reaching the patient or
consumer. The intercepted error term should reflect the stage at which theerror occurred, rather than the stage at which it was intercepted.
Issue
The word “issue” for the purpose of MedDRA is used as a general term,
which does not necessarily point to a failure or defect when paired with aproduct or a device.
L
Label
Label refers to display of written, printed, or graphic matter upon thecontainer or packaging.
Labelled drug-disease interaction medication error
This medication error refers to the situation when a patient is prescribed,
dispensed, or administered a drug that is documented in the drug label as
having the potential to exacerbate or worsen the patient's pre-existing
disease(s). Example: A patient has a medical history of having bleeding
gastric ulcers. However, the patient was inadvertently prescribed anddispensed several doses of aspirin.
Labelled drug-drug interaction medication error
This medication error refers to the situation when a patient is prescribed,
dispensed, or administered a drug that is documented in the drug label tocause a drug to drug interaction with the patient's existing medication(s).
Example: Patient became pregnant whilst taking an antifungal drug and an
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oral contraceptive. This interaction is clearly stated in the product data
sheet.
Labelled drug-food interaction medication error
This medication error refers to the situation when a patient is prescribed,
dispensed, or administered a drug that is documented in the drug label tocause an expected adverse event with patient's consumed food.
Example: Patient drank grapefruit juice whilst taking a calcium channel
blocker and the calcium channel blocker is labeled for grapefruit juice
interaction.
Lower gastrointestinal tract
For purposes of MedDRA the following constitute the lower
gastrointestinal tract - small intestine (duodenum, jejunum, ileum) large
intestine-cecum (and the vermiform appendix attached to the cecum)colon (ascending colon, transverse colon, descending colon and sigmoid
flexure), rectum, and anus.
Lower respiratory tract
For purposes of MedDRA the lower respiratory tract is comprised ofbronchi, bronchioles, alveoli and lungs.
M

Manufacturing stability testing
For the purposes of term selection and analysis of MedDRA-coded data,
manufacturing stability testing refers to the stage of the manufacturing
process where testing is performed to provide evidence on how the qualityof a drug substance or drug product varies with time under the influence ofa variety of environmental factors such as temperature, humidity, andlight. Stability testing permits the establishment of recommended storage
conditions, retest periods and shelf lives.
Medication error
Medication errors are defined as any preventable event that may cause orlead to inappropriate medication use or patient harm while the medication
is in the control of the health care professional, patient or consumer. Such
events may be related to professional practice, health care products,
procedures and systems, including prescribing, order communication,
product labeling, packaging and nomenclature, compounding, dispensing,
distribution, administration, education, monitoring and use.
National Coordinating Council for Medication Error Reporting andPrevention (US); 2001. About medication errors.
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https://www.nccmerp.org/about-medication-errors. Accessed December 1,
2017.
Medication monitoring error
For the purposes of term selection and analysis of MedDRA-coded data, a
medication monitoring error is an error that occurs in the process ofmonitoring the effect of the medication through clinical assessment and/or
laboratory data. It can also refer to monitoring errors in following
instructions or information pertinent to the safe use of the medication.
MisuseFor the purposes of term selection and analysis of MedDRA-coded data,
misuse is the intentional use for a therapeutic purpose by a patient or
consumer of a product – over-the-counter or prescription – other than asprescribed or not in accordance with the authorised product information.
O
Occupational exposure
Occupational exposure encompasses the “chronic” exposure to an agent(including therapeutic products) during the normal course of one's
occupation, and could include additional scenarios in specific regulatory
regions. For example, occupational exposure may additionally relate to amore acute, accidental form of exposure that occurs in the context of one's
occupation.
Off Label Use
For the purposes of term selection and analysis of MedDRA-coded data,
the concept of “off label use” relates to situations where a healthcare
professional intentionally prescribes, dispenses, or recommends a productfor a medical purpose not in accordance with the authorised productinformation. When recording off label use, consider that productinformation and/or regulations/requirements may differ between regulatory
regions.

Out of specification test results
For the purposes of term selection and analysis of MedDRA-coded data,out of specification test results refers to test results performed during thepharmaceutical product manufacturing process that fall outside thespecifications or acceptance criteria established in drug applications, drug
master files, official compendia, or by the manufacturer. It also applies toall-in process laboratory tests that are outside of establishedspecifications.

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Overdose
For the purposes of term selection and analysis of MedDRA-coded data,
overdose is more than the maximum recommended dose (in quantity
and/or concentration), i.e., an excessive dose.
P
Precipitate
Precipitate is substance separated from a solution or suspension bychemical or physical change usually as an insoluble solid which is notnormal for the product.
Preparation
A medicinal substance that is ready for use (e.g., a preparation for colds).
http://www.merriam-webster.com/medical/preparation
Prescribing error
Prescribing errors may be made in the hand of physicians or other
healthcare professionals who have the prescription authority.
ProcedureThis term relates to concepts currently in SOC Injury, poisoning andprocedural complications under HLGT Procedural related injuries andcomplications NEC and in SOC Surgical and medical procedures.
Product
In the context of MedDRA, "product" can refer to various types of products
intended for human use such as drugs (prescription and over the counter),biologics, vaccines, combination products, devices, nutraceuticals, dietary
supplements, etc.
Product coating incomplete
Product coating incomplete refers to the outer coating of a product when it
does not entirely cover the product and can appear blotchy, splattered orspeckled.
Product colour issue
Product color issue is when the product color is not uniform; color has
faded, or turned to a different color/shade.
Product dosage form confusion
Product dosage form confusion is a misinterpretation of the dosage formof a product which may potentially result in a medication error.
Product label confusion
Product label confusion is a misinterpretation of the appearance and/or
content of a product label which may potentially result in a medication
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error. This may be due to similarity with another product's label or due to
confusing information on a single product label.
Product name confusion
Product name confusion is a misinterpretation of the correct name of a
product which may result in a medication error. This may be due to amisleading name, or due to similar-looking or sounding product names.
Product odour abnormal
A change in the normal odor of the product.
Product packaging confusion
Product packaging confusion is a misinterpretation of the appearance of a
product's packaging which may potentially result in a medication error.
This may be due to similarity with the appearance of another product's
packaging or due to confusing appearance or presentation of a single
product's packaging.
Product quality issues
Product quality issues are abnormalities that may be introduced during the
manufacturing/labeling, packaging, shipping, handling or storage of the
products.
Product storage
HLT Product distribution and storage issues in SOC Product issues isintended to cover issues with the storage of products by manufacturers,
distributors, wholesalers, etc. In contrast, product storage issues by endusers such as healthcare professionals, patients, and consumers are
considered to be medication errors and are represented by theappropriate medication error terms in HLT Product storage errors andissues in the product use system in SOC Injury, poisoning and procedural
complications.
Product taste abnormal
A change in the normal taste of the product.
Progression ofMovement forward; advancement. Continuously spreading or increasing
in severity.
Prophylaxis ofProtective treatment for or prevention of disease. For the purposes ofterm placement in MedDRA, the use of modifiers “prophylaxis” and“prevention of” is interchangeable.
R
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Rate
The amount of drug (dose) administered per unit of time

Recurrent
Occurring or appearing again or repeatedly. For the purposes of term
placement in MedDRA, the modifiers “relapse” and “recurrent” aresynonymous.
S
Seal
A seal refers to an outer wrap on the closure or a liner attached to thecontainer underneath the closure to either protect the product or act as atamper evident feature.
Sedimentation
Sedimentation is the settling of product or foreign material to the bottom ofa vial/container which is not normal for the product.
Sore/soreness/sores
For purposes of MedDRA, “sore” and “soreness” terms are used for pain.
“Sore” terms, unless clearly addressed to a concept e.g. LLT Bed sore
linked to PT Decubitus ulcer – are mainly placed under either pain related
PTs or PTs indicating inflammation. “Sores” are considered lesions of theskin or mucous membrane frequently associated with pain, inflammation
etc., depending on the context.
Solubility
See the concept description for dissolution.
Strength
Refers to a concentration of active ingredient found in a particular dosage
form.
Subacute
Between acute and chronic: course of a disease of moderate duration or
severity. Please see definitions of “acute” and “chronic.”
T
Technique
The manner of performance, method, operation, procedure, or details(e.g., pharmaceutical technique, aseptic technique) used to prepare a
product.
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Tenderness
For purposes of MedDRA tenderness terms are defined as sub-conceptsof pain and mainly subordinated to “Pain” or to “-algia” PTs unless theyclearly address a single concept (e.g., PT Abdominal reboundtenderness).
Thrombophlebitis
Inflammation of a vein (phlebitis) associated with thrombus formation(thrombosis). The MSSO acknowledges the international use ofthrombophlebitis/phlebothrombosis/vein thrombosis interchangeably, but
MedDRA recognizes them as separate unique concepts. MedDRA also
makes a distinction between superficial and deep vein thrombosis. Whenthrombosis occurs in the lower extremity, it is often called deep venous
thrombosis/thrombophlebitis (DVT); when superficial vessels are involved,
it is superficial thrombosis/thrombophlebitis.
U
Underdose
For the purposes of term selection and analysis of MedDRA-coded data,
underdose is the administration of less than the minimum recommended
dose (in quantity and/or concentration).
Upper gastrointestinal tract
In MedDRA the following organs constitute the upper gastrointestinal tract:
mouth (buccal cavity; including salivary glands, mucosa, teeth, andtongue), oesophagus and stomach which includes the cardia, fundus,
body, and pylorus.
Upper respiratory tract
In MedDRA the upper respiratory tract is comprised of nose, paranasal
sinuses, pharynx, larynx and trachea.
W
Worsened/worsening
See “aggravated.” For the purposes of term placement in MedDRA, theuse of modifiers exacerbated, aggravated and worsened isinterchangeable.

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