# Presentation: 521074

## Quality Assurance of Tests for Sexually Transmitted Infections

- Michael A. Noble MD FRCPC
- CDC Quality Assurance Meeting, November 29, 2000

## Sexual activity directly accounts for 60-70 percentof microbiology laboratory activity.

- The most commonly submitted sample is urine from women with acute or recurrent urinary tract infection.
- The most common cause of urinary tract infectionsin women is recent sexual activity.
- Tests for sexually transmitted infections are thesecond most commonly submitted samples send to medical laboratories.

- Sexual activity directly accounts for 60-70 percentof microbiology laboratory activity.

## In North America

- Sexually transmitted infections cycle with a periodicity of 10-20 years.
- Peaks in 1920s, 1940s, 1960s, 1980s
- Progressive decreasing detection and reporting rates throughout 1990s
- Rate of sexually transmitted infections lower now compared to the last 20 years.
- Diagnostic assays for sexually transmitted infections continuously improves.

- North America experience does notnecessarily reflect world-wide experience.

## Why STI Diagnosis is Important

- STIs rapidly spread throughout communities.
- STIs can be  associated with acute illness.
- STIs can be associated with chronic illness.
- STIs can be associated with remote illness.
- Ulcerative STI associated transmission of other illnesses, especially HIV.
- Syphilis
- Chancroid
- LGV

## Sexually Transmitted Infections

**Bacterial**
- Neisseria gonorrhoeae
- Chlamydia trachomatis
- Treponema pallidum
- Haemophilus ducryei (chancroid)
- Lymphogranuloma
- Mycoplasma
**Viruses**
- Herpes simplex II
- Hepatitis B
- Hepatitis C
- HIV
- Papillomavirus

**Yeasts and fungi**
- Candida albicans
- Candida glabrata
- Candida tropicalis
**Parasites**
- Trichomonas vaginalis
- Entamoeba histolytica

## Sexually Transmitted Infections

- Neisseria gonorrhoeae
- Chlamydia trachomatis
- Treponema pallidum

## Gonorrhea

- Acute tenosynovitis

- NeonatalConjunctivitis

- P.I.D.

- UrethralStrictures

- ChronicArthritis

- Infertility

- F.H.C.-Hepatitis

- Sepsis

## Chlamydiatrachomatis

- Acute Arthritis

- NeonatalConjunctivitis

- P.I.D.

- ChronicArthritis

- Infertility

*Chlamydia**trachomatis*

- Hepatitis

## Syphilis

- CardiovascularGumma

- Neurosyphilis**Meningitis****Tabes dorsalis****General paresis**

- HIV Transmission.

- CongenitalTransmission

- ChronicArthritis

- Hepatitis

- Lymph-adenopathy

## Test Procedures Requiring EQA(Those with Readily Available EQA Programs)

*Neisseria gonorrhoeae*
- Gram stain
- Culture
- PCR
*Chlamydia trachomatis*
- DFA
- EIA
- PCR
- Culture
*Treponema pallidum*
- Serological tests for Syphilis
- VDRL, RPR, FTA-abs, MHA-tp

## What is available for international guidance for Quality Assessment forMedical Laboratory Tests?

## Standards for Consideration (1)

- ISO 17025/ISO 15189  and NCCLS GP17A
- 5.6.5	The laboratory shall participate in organised inter-laboratory comparisons, such as external quality assessment and proficiency testing schemes, that encompass the extent and complexity of analytical and diagnostic procedures used by the laboratory.  The laboratory director and management shall monitor the results of external quality assessment and proficiency testing and participate in the implementation and documentation of corrective actions. ***Schemes should be consistent with ISO Guide 43***.

## Standards for Consideration (2)

- . *ISO Guide 43*
*These programmes should, as far as possible, provide clinically relevant challenges that mimic patient samples and that check the entire examination process including pre- and post-analytical procedures*

## The

- Laboratory
- Cycle
- Bartlett ‘80

- The Patient

- Report Creation

- Report Transmission

- ReportInterpretation

- Collection

- Transport

- Accession

- Analysis

- Test Selection

- Pre
- AnalytIc

- Post
- AnalytIc

## When was the last time a clinical laboratory commonly received samples in the form of a small glass vial that contained a small amount of white powder that required rehydration?

*Mimicing patient samples*

## What constitutes a Guide 43“clinically relevant challenge that mimics patient samples” 

- Gram stain with host elements and proportionate microbial elements
- DFA material with host elements and proportionate microbial elements.
- EIA material with bacterial contaminants and proportionate microbial elements.
- PCR material that may contain inhibitors.
- Antibody challenges in fresh human serum.

## Standards for Consideration (3)

- ISO 17025/ ISO 15189 (2)
- 5.6.6	Whenever a formal inter-laboratory comparison program is not available, the laboratory shall develop a mechanism for determining the accuracy of those procedures not otherwise evaluated.  Whenever possible, this mechanism shall utilise externally derived challenge materials such as exchange of samples with other laboratories.  The laboratory director and management shall monitor the results of this mechanism proficiency testing and participate in the implementation and documentation of corrective actions.

## Alternatives to formal EQA(In decreasing order of acceptability)

- Self-initiated peer-group inter-laboratory comparison. (    )
- Self-initiated inter-laboratory comparison. (   )
- Challenge review of known positive-negative clinical material ( )
- Challenge review of control material ()

## Challenges with many Proficiency Tests currently available

- Gram stain:			usually with bacteria only
- Culture				usually lyophilyzed material only
- EIA/DFA				assay and brand specific
- PCR				Does not contain host material
- VDRL/RPR/FTA (blood)		frozen human serum
- VDRL (csf)				csf not commonly available

## Challenges of compliance with Guide 43 requirements

- Making relevant materials requires considerable research and development.
- Non-lyophilized material tends to degenerate rapidly with time.
- Fresh human serum degrades quickly.
- Samples require temperature and time control in transportation.

## Proficiency Testing  of Neisseria culture assays

- Challenges (and some solutions)
- Dies quickly in transport medium
- 50 percent die-off in 24 hours
- Improved (7 day) survival with 5% CO2
- Unstable recovery from lyophylization
- Bacterial identification should be challenged
*Neisseria cinerea* (low virulence commensal)
- Colonies larger, 			Gluocse negative,
- Enzyme substrate false positive	DFA negative
- Agglutination false positive

## Gram stain challengecontaining gram negative diplococci (intra- and extracellular) with human neutrophils.

**Gram stain challenge****containing gram negative diplococci (intra- and extracellular) with human neutrophils.**

## Syphilis Serology

## Proficiency Testing for Syphilis Serology

- Fresh human serum.
- Test across the range of  dilutions typically found in the clinical samples.

**Clinical Interpretation of VDRL and RPR ****is based on both qualitative ****(positive/negative)**** ****and quantitative ****(low titre/high titre)**** results.**

## The

- Laboratory
- Cycle
- Bartlett ‘80

- The Patient

- Report Creation

- Report Transmission

- ReportInterpretation

- Collection

- Transport

- Accession

- Analysis

- Test Selection

- Pre
- AnalytIc

- Post
- AnalytIc

## Pre-analytic phase testing
Can the laboratory transport samples quickly and safely?
Analytic phase Testing 
Can the laboratory identify organisms when present?
Can the laboratory distinguish between contaminants and positives?
Can the laboratory recognize true negative samples?
Post-analytic phase testing
Post-analytic phase testing
Can the laboratory provide information that is accurate, clinically relevant, unambiguous and interpretable?

- Can the laboratory transport samples quickly and safely?
- Analytic phase Testing
- Can the laboratory identify organisms when present?
- Can the laboratory distinguish between contaminants and positives?
- Can the laboratory recognize true negative samples?
- Post-analytic phase testing
- Post-analytic phase testing
- Can the laboratory provide information that is accurate, clinically relevant, unambiguous and interpretable?

## Quality Control of PT materials

**Are you providing really providing what you are saying you are providing?**
**Pre-test sampling:**
- 	MIL STD 105E based random sampling charts for acceptance sampling (5-15% sampling for 98-99% confidence)
**Same-time sampling:**
- 	Program and reference laboratory testing
**Post-test sampling:**
- 	Sample call-back and review

## Programs that comply with Guide 43 requirements

**Programs with some compliance**
- C.A.P. - USA
- UK-NEQAS – UK
- QMPLS – Ontario, Canada
- CMPT – British Columbia, Canada
- 	***Note this list should not be considered ******	******complete or comprehensive***

## Goal of PT Program Assistance

- Assist with establishment of program core
- Assist with program start-up and provision of training and start-up materials
- Serve as reference resource for regionally based local program

**Timeframes vary with situation**

## In Summary

- Sexually Transmitted Infections are commonly associated with fastidious or non-growing organisms, making laboratory diagnosis challenging.
- Tests for Sexually Transmitted Infections are critical for diagnosis and documentation and need critical quality control.
- Development of PT materials can be expensive and challenging, but many issues have been addressed.
- Quality materials are available existing programs.