**Guidance for Industry**

**and FDA Staff**

**Class II Special Controls Guidance Document: Drug Metabolizing Enzyme
Genotyping System**

**Document issued on: \[[Insert release date of FR Notice\]]{.mark}**

For questions regarding this document contact Courtney Harper at
240-276-0443 or by email at courtney.harper@fda.hhs.gov.

![](media/image1.png)

**U.S. Department of Health and Human Services**

**Food and Drug Administration**

**Center for Devices and Radiological Health**

**Office of In Vitro Diagnostic Device Evaluation and Safety**

**Division of Chemistry and Toxicology Devices**

**Preface**

**Public Comment**

> Written comments and suggestions may be submitted at any time for
> Agency consideration to Division of Dockets Management, Food and Drug
> Administration, 5630 Fishers Lane, Room 1061, (HFA-305), Rockville,
> MD, 20852. Alternatively, electronic comments may be submitted to
> <http://www.fda.gov/dockets/ecomments>. Please identify your comments
> with the Docket No. 2005D-0068. Comments may not be acted upon by the
> Agency until the document is next revised or updated.

**Additional Copies**

> Additional copies are available from the Internet at:
> <http://www.fda.gov/cdrh/oivd/guidance/1551.pdf>, or to receive this
> document by your fax machine, call the CDRH Facts-On-Demand system at
> 800-899-0381 or 301-827-0111 from a touch-tone telephone. Press 1 to
> enter the system. At the second voice prompt, press 1 to order a
> document. Enter the document number 1551 followed by the pound sign
> (#). Follow the remaining voice prompts to complete your request. For
> questions regarding the use or interpretation of this guidance
> contact: Courtney Harper at 240-276-0443 or by email at
> courtney.harper@fda.hhs.gov.
>
> **Table of Contents**

[1. Introduction 4](#introduction)

[2. Background 5](#background)

[3. The Content and Format of an Abbreviated 510(k) Submission
5](#the-content-and-format-of-an-abbreviated-510k-submission)

[4. Scope 7](#scope)

[5. Risks to Health 8](#risks-to-health)

[6. Device Description 9](#device-description)

[Intended Use 9](#intended-use)

[Test Methodology 9](#test-methodology)

[Test Algorithms 10](#test-algorithms)

[Test Results 10](#test-results)

[7. Performance Characteristics 10](#performance-characteristics)

[Preanalytical Factors 11](#preanalytical-factors)

[Quality Control 11](#quality-control)

[Analytical Factors 12](#__RefHeading___Toc91398890)

[8. Method Comparison 13](#method-comparison)

[Clinical Validation 14](#clinical-validation)

[Study Samples 14](#study-samples)

[Sample collection and handling conditions
14](#__RefHeading___Toc91398894)

[9. Software 15](#software)

[10. Labeling 16](#labeling)

**Guidance for Industry and FDA Staff**

**Class II Special Controls Guidance Document: Drug Metabolizing Enzyme
Genotyping System**

***This guidance represents the Food and Drug Administration\'s (FDA\'s)
current thinking on this topic. It does not create or confer any rights
for or on any person and does not operate to bind FDA or the public. You
can use an alternative approach if the approach satisfies the
requirements of the applicable statutes and regulations. If you want to
discuss an alternative approach, contact the FDA staff responsible for
implementing this guidance. If you cannot identify the appropriate FDA
staff, call the number listed on the title page of this guidance.***

# Introduction

This document was developed as a special control to support the
classification of drug metabolizing enzyme (DME) genotyping systems into
class II (special controls).  A DME genotyping system is a device
intended for use in testing DNA to identify the presence or absence of
human genotypic markers encoding a drug metabolizing enzyme. This device
is used as an aid in determining treatment choice and individualizing
treatment dose for therapeutics that are metabolized primarily by the
specific enzyme about which the system provides genotypic information.

This guidance is issued in conjunction with a *Federal Register* notice
announcing the classification of DME genotyping systems. Any firm
submitting a 510(k) premarket notification for a DME genotyping system
will need to address the issues covered in the special control
guidance.  However, the firm need only show that its device meets the
recommendations of the guidance or in some other way provides equivalent
assurances of safety and effectiveness.

FDA\'s guidance documents, including this guidance, do not establish
legally enforceable responsibilities.  Instead, guidances describe the
Agency\'s current thinking on a topic and should be viewed only as
recommendations, unless specific regulatory or statutory requirements
are cited.  The use of the word *should* in Agency guidances means that
something is suggested or recommended, but not required.

**The Least Burdensome Approach**

The issues identified in this guidance document represent those that we
believe should be addressed before your device can be marketed. In
developing the guidance, we carefully considered the relevant statutory
criteria for Agency decision-making. We also considered the burden that
may be incurred in your attempt to follow the statutory and regulatory
criteria in the manner suggested by the guidance and in your attempt to
address the issues we have identified. We believe that we have
considered the least burdensome approach to resolving the issues
presented in the guidance document. If, however, you believe that there
is a less burdensome way to address the issues, you should follow the
procedures outlined in the document, "A Suggested Approach to Resolving
Least Burdensome Issues." It is available on our Center web page at:
<http://www.fda.gov/cdrh/modact/leastburdensome.html>.

# Background

FDA believes that special controls, when combined with the general
controls, provide reasonable assurance of the safety and effectiveness
of DME genotyping systems. A manufacturer who intends to market a device
of this type should (1) conform to the general controls of the Federal
Food, Drug, and Cosmetic Act (the Act), including the premarket
notification requirements described in [21 CFR
807](http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=807&showFR=1)
Subpart E, (2) address the specific risks to health associated with DME
genotyping systems identified in this guidance, and (3) obtain a
substantial equivalence determination from FDA prior to marketing the
device.

This guidance document identifies the classification regulation and
product code for DME genotyping systems. (Refer to Section 4 --
**[Scope](http://www.fda.gov/cdrh/oivd/guidance/#__RefHeading___Toc52173678).)** 
In addition, other sections of this guidance document list the risks to
health identified by FDA and describe measures that, if followed by
manufacturers and combined with the general controls, will generally
address the risks associated with these assays and lead to a timely
premarket notification \[510(k)\] review and clearance.  This document
supplements other FDA documents regarding the specific content
requirements of a premarket notification submission.  You should also
refer to [21 CFR
807.87](http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?FR=807.87)
and other FDA documents on this topic, such as the **510(k) Manual -
Premarket Notification: 510(k) - Regulatory Requirements for Medical
Devices**, <http://www.fda.gov/cdrh/manual/510kprt1.html>.

As explained in "**The New 510(k) Paradigm - Alternate Approaches to
Demonstrating Substantial Equivalence in Premarket Notifications; Final
Guidance**[^1]," a manufacturer may submit either a Traditional 510(k)
or an Abbreviated 510(k). FDA believes an Abbreviated 510(k) provides
the least burdensome means of demonstrating substantial equivalence for
a new device, particularly when FDA has issued a guidance document that
provides recommendations on what should be addressed in a submission for
the device. Alternatively, manufacturers considering modifications to
their own cleared devices may lessen the regulatory burden by submitting
a Special 510(k).

# The Content and Format of an Abbreviated 510(k) Submission 

An Abbreviated 510(k) submission must include the required elements
identified in 21 CFR 807.87, including the proposed labeling for the
device sufficient to describe the device, its intended use, and the
directions for its use. In an Abbreviated 510(k), FDA may consider the
contents of a summary report to be appropriate supporting data within
the meaning of 21 CFR 807.87(f) or (g); therefore, we recommend that you
include a summary report. The report should describe how this guidance
document was used during the device development and testing and the
methods or tests used. The report should also include a summary of the
test data or description of the acceptance criteria applied to address
the risks identified in this document, as well as any additional risks
specific to your device. This section suggests information to fulfill
some of the requirements of 21 CFR 807.87 as well as some other items
that we recommend you generally include in an Abbreviated 510(k).

> **Coversheet**
>
> The coversheet should prominently identify the submission as an
> Abbreviated 510(k) and cite the title of this guidance document.
>
> **Proposed labeling**
>
> Proposed labeling should be sufficient to describe the device, its
> intended use, and the directions for its use. (Refer to Section 10 for
> specific information that you should include in the labeling for this
> type of device.)
>
> **Summary report**

We recommend that the summary report contain the following:

-   A description of the device and its intended use. You should also
    submit an \"indications for use\" enclosure.[^2] (Refer to Section 6
    for specific information that you should include in the intended use
    and device description for this type of device.)

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-   A description of the device design. We recommend that the
    description include a complete discussion of the performance
    specifications and, when appropriate, detailed, labeled drawings of
    the device.

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-   Identification of the Risk Analysis method(s) used to assess the
    risk profile in general, as well as the specific device's design and
    the results of this analysis. (Refer to Section 5 for the risks to
    health generally associated with the use of this device.)

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-   A discussion of the device characteristics that address the risks
    identified in this class II special controls guidance document, as
    well as any additional risks identified in your risk analysis.

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-   A brief description of the test method(s) you have used or intend to
    use to address each performance aspect identified in Sections 7 and
    8 of this guidance document. If you follow a suggested test method,
    you may cite the method rather than describing it. If you modify a
    suggested test method, you may cite the method, but should provide
    sufficient information to explain the nature of and reason for the
    modification. For each test, you may either (1) present the data
    resulting from the test in clear and concise form, such as a table,
    **[or]{.underline}** (2) describe the acceptance criteria that you
    will apply to your test results.[^3] (See also 21 CFR 820.30,
    Subpart C - Design Controls for the Quality System Regulation.)

-   If you choose to rely on a recognized standard for any part of the
    device design or testing, you may include either: (1) a statement
    that testing will be conducted and meet specified acceptance
    criteria before the product is marketed, or (2) a declaration of
    conformity to the standard.[^4] Because a declaration of conformity
    is based on results from testing, we believe you cannot properly
    submit a declaration of conformity until you have completed the
    testing the standard describes. For more information, please refer
    to section 514(c)(1)(B) of the Act and the FDA guidance, **Use of
    Standards in Substantial Equivalence Determinations; Final Guidance
    for Industry and FDA**,
    <http://www.fda.gov/cdrh/ode/guidance/1131.html>.

If it is not clear how you have addressed the risks identified by FDA or
additional risks identified through your risk analysis, we may request
additional information about aspects of the device's performance
characteristics. We may also request additional information if we need
it to assess the adequacy of your acceptance criteria. (Under 21 CFR
807.87(l), we may request any additional information that is necessary
to reach a determination regarding substantial equivalence.)

As an alternative to submitting an Abbreviated 510(k), you can submit a
Traditional 510(k) that provides all of the information and data
required under 21 CFR 807.87 and described in this guidance. A
Traditional 510(k) should include all of your methods, data, acceptance
criteria, and conclusions. Manufacturers considering modifications to
their own cleared devices should consider submitting Special 510(k)s.

The general discussion above applies to any device subject to a special
controls guidance document. The following is a specific discussion of
how you should apply this special controls guidance document to a
premarket notification for DME genotyping systems.

# Scope

The scope of this document is limited to the following devices as
described in 21 CFR 862.3360 (product code NTI):

[21 CFR 862.3360]{.underline} Drug metabolizing enzyme genotyping system

A drug metabolizing enzyme genotyping system is a device intended for
use in testing DNA to identify the presence or absence of human
genotypic markers encoding a drug metabolizing enzyme. This device is
used as an aid in determining treatment choice and individualizing
treatment dose for therapeutics that are metabolized primarily by the
specific enzyme about which the system provides genotypic information.

DME genotyping systems that are multiplex tests may be run on
instrumentation for clinical multiplex test systems. Instrumentation for
clinical multiplex test systems is regulated under 21 CFR 862.2570.
Guidance for such instrumentation is available in the FDA Guidance for
Industry and FDA Staff "*Class II Special Controls Guidance Document:
Instrumentation for Clinical Multiplex Test Systems*." If your device
includes a DME genotyping assay with instrumentation for clinical
multiplex test systems for that assay, you may submit the information
for both devices within one 510(k). Although instrumentation for
clinical multiplex test systems (a Class II device) may be used with a
DME genotyping system, the guidance document, "*Replacement Reagent and
Instrument Family Policy"*, (available at
http://www.fda.gov/cdrh/oivd/guidance/950.pdf) does not apply to DME
genotyping systems for use with instrumentation for clinical multiplex
test systems.

# Risks to Health

Failure to correctly identify the DME genotype could result in incorrect
patient management decisions. In these situations a patient might be
prescribed an incorrect drug or drug dose with concomitant increased
risk of adverse reactions due to increased or decreased drug metabolism.
Likewise, failure to properly interpret genotyping results could lead to
incorrect prediction of phenotype and result in incorrect patient
management decisions.

The information provided by this type of genetic test should only be
used to supplement other tools for therapeutic decision-making in
conjunction with routine monitoring by a physician. The effect that a
specific DME allele has on drug metabolism may vary depending on the
specific drug, even for drugs within a specific class. Effects of
specific alleles on drug metabolism are well-documented for some drugs;
for other drugs, they are less well-documented. Therefore, clinicians
should use professional judgement when interpreting results from this
type of test. In addition, results from this type of assay should not be
used to predict a patient's response to drugs in cases where either, 1)
the drug metabolizing enzyme activity of the allele has not been
determined, or 2) the drug's metabolic pathway has not been clearly
established.

In the table below, FDA has identified the risks to health generally
associated with the use of DME genotyping systems addressed in this
document.  The measures recommended to mitigate these identified risks
are given in this guidance document, as shown in the table below.  We
recommend that you conduct a risk analysis, prior to submitting your
premarket notification, to identify any other risks specific to your
device.  The premarket notification should describe the risk analysis
method.  If you elect to use an alternative approach to address a
particular risk identified in this document, or have identified risks
additional to those in this document, you should provide sufficient
detail to support the approach you have used to address that risk.

  ----------------------------------- -----------------------------------
  **Identified risk**                 **Recommended mitigation measures**

  Failure to correctly identify       Sections 7, 8, and 9
  genotype encoding for a DME         

  Failure to properly interpret       Section 10
  genotyping results                  
  ----------------------------------- -----------------------------------

# Device Description

You should describe the following information in your 510(k).

## Intended Use

The intended use should specify the genotype(s) the test is intended to
detect, the general clinical utility of detecting the genotype, and the
specific populations to which the test is targeted. The intended use
should specify the drug metabolizing enzyme encoded by the genotype.

Some tests may have multiple intended uses (e.g., multiple DME's). When
separate studies are needed to support the multiple intended uses, you
should submit separate 510(k) applications for each intended use. You
should consult the appropriate review divisions in OIVD for advice on
submitting applications for test systems with multiple intended uses.

## Test Methodology

You should describe in detail the methodology used by your device to
detect genotypes. For example, you should describe the following
elements, where applicable for your device:

-   Test platform[^5] (e.g., flow cytometry, instrumentation for
    clinical multiplex test systems).

-   Composition and spatial layout of arrays or other spatially fixed
    platforms.

-   Methods used in attaching the probe material to a solid surface, if
    applicable.

-   Sequence or identity of oligonucleotides, primers, probes, or other
    capture elements.

-   Hybridization conditions, washing procedures and drying conditions
    (e.g., temperature, length of time).

-   Specificity of probes for the sequence of interest, especially when
    pseudogenes or sequence-related genes exist.

-   Methodology for DNA extraction that you provide or that you
    recommend for users.

-   Assay components such as buffers, enzymes, fluorescent dyes,
    chemiluminescent reagents, other signaling and signal amplification
    reagents, instruments.

-   External controls that you recommend or provide to users.

-   Any internal controls, including those that mitigate miscalls
    (inaccurate results) due to genotypes that your device does not
    detect.

Where applicable for your device, you should describe the quality
control design specifications in place to address the following:

-   Correct placement and identity of instrument features (e.g.,
    probes).

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-   For multiplexed tests in which the target molecules will contact a
    number of different probes, the potential for specific and
    non-specific probe cross-hybridization.

-   Prevention of probe cross-contamination, for multiplexed tests in
    which many probes are handled during the manufacturing process.

Illustrations or photographs of non-standard equipment or methods can be
helpful in understanding novel methodologies.

## Test Algorithms

Because of the large number of polymorphisms found within some DME
genes, and the fact that some polymorphisms may be common to various
alleles, you should explain how the test algorithms were developed to
report DME genotype, if applicable. 

## Test Results

You should provide examples of the test reports (e.g., printouts) that
are generated for the clinician. These reports should be consistent with
current recommendations of genetics professional societies, if
applicable, and should contain adequate interpretation guidelines for
the use of the ordering physician/counselor.

Where applicable, reports should describe the polymorphisms identified
by your test and the methodology and technology used for detection.  You
should identify representative literature references describing
genotypic interpretations, or phenotypic predictions, if applicable, to
enable users to access information about specific genotypes. We expect
that for most 510(k) applications, appropriate literature references
will be available. If such supporting information is not available, you
should provide information based on the clinical studies you conducted
to address clinical validity of your device.

# Performance Characteristics

In your 510(k), you should detail the study design you used to evaluate
each of the performance characteristics outlined below. This should
include information such as:

-   Description of the samples you used in testing (including types of
    samples, preparation or origin, number of samples and how the
    samples specifically represent your intended use samples).

-   Descriptions of the computations and statistical analyses you used
    to evaluate your data.

-   Explanations, if there were any deviations from your protocol.

For each of the performance characteristics described below, you should
also provide a clear description of all results and acceptance criteria
in your 510(k).

The issues described below generally apply, regardless of the technology
used by the device to detect the DME genotype. If you make additional
claims for other performance characteristics not mentioned below, you
should describe the study designs and results you used to support them.

## Preanalytical Factors

Consideration of preanalytical factors is critical for high-quality
genetic tests. If you intend to provide reagents for extraction and
preparation of DNA for testing, you should validate each step in the
preanalytical process for its effects on reproducibility, accuracy, and
stability of product and describe study design and results addressing
this issue in the 510(k). Your external site studies (e.g.,
reproducibility, method comparison) should include evaluation of the
preanalytical process.

If you do not intend to provide reagents for DNA extraction and
preparation as part of the assay, you should provide specifications for
the reagents needed and for assessing the quality of the assay input
DNA, so that the user can select appropriate reagents. You should
describe, in your 510(k), the study design and results you used to
determine these specifications. In this case, we recommend that in
studies establishing the performance of your device, you permit sites to
use any extraction method they choose, provided that it meets your
test's specifications. In this way, you can evaluate any effect of
variations in preanalytical processes on your device performance.

You should evaluate the accuracy and precision of your assay, including
DNA extraction, from all the sources of DNA that you recommend for your
assay (e.g., blood, PBMC, buccal swab). You should also evaluate all
sample collection and storage options you recommend (e.g.,
heparin-preserved vs. EDTA-preserved blood, stored vs. fresh sample).
Your validation of appropriate storage conditions should include both
the sample and the extracted product.

You should evaluate the stability of all of your reagents and
recommended samples.

## Quality Control

DME genotyping systems should include both positive and negative
controls. Controls should approximate sample composition and DNA
concentration in order to adequately challenge the system.

You should describe the following concerning quality control and
calibration material:

-   The nature and the function of the various controls that you include
    with, or recommend for, your system. These controls may differ
    between individual technologies, but they should enable the user to
    determine if all steps and critical reactions have proceeded
    properly and without contamination or cross-hybridization.

-   Your methods for value assignment and validation of control and
    calibrator material.

-   Your methods for establishing quality control and calibration
    procedures, including your recommended frequency.

We recommend that you provide for the calibration of DME genotyping
systems where appropriate.

[]{#__RefHeading___Toc91398890 .anchor}

## Analytical Factors

###  [Analytical Sensitivity and Assay Limits]{.underline}

> You should validate the analytical sensitivity of your test. This may
> be defined as the lowest amount of genomic DNA for which the assay can
> detect genotypes with a given accuracy and precision. You should also
> approximate the volume of the clinical sample required to generate
> this minimum input. We recommend that you determine analytical
> sensitivity using samples containing genomic DNA at varying
> concentrations. You should test a statistically determined number of
> replicates at each DNA level. Similarly, you should determine the
> upper limit of the assay, in terms of DNA concentration and sample
> volume.

###  [Interference]{.underline}

> Where applicable, you should evaluate cross-contamination of your
> device. In particular, you should perform studies to characterize
> potential carryover by alternating specimens of known genotype. You
> should also evaluate homologous gene sequences for cross-reactivity.
>
> Potential interfering substances may not always be removed by sample
> preparation, and may also interfere with sample preparation.
> Therefore, we recommend that you characterize the effects of potential
> interfering substances on assay performance.  Examples of experimental
> designs, including guidelines for selecting interfering substances for
> testing, are described in detail in "Interference Testing in Clinical
> Chemistry; Approved Guideline" (NCCLS document EP7-A, 2002).
>  Potential interfering substances can include compounds normally found
> in serum, such as triglycerides, hemoglobin (for specimens other than
> blood), bilirubin, lipids, and exogenous compounds such as common
> drugs.

###  [Precision (Repeatability/Reproducibility)]{.underline}

> You should fully examine the reproducibility of your DME genotyping
> system. "Evaluation of Precision Performance of Clinical Chemistry
> Devices" (NCCLS Document EP5-A) and "User Protocol for Evaluation of
> Qualitative Test Performance" (NCCLS EP-12A) include guidelines for
> experimental design, computations, and a format for stating
> performance claims.  We recommend that you incorporate the following
> in the design of your reproducibility studies:

-   Design the study so that you can characterize intra- and inter-assay
    reproducibility.

-   Use appropriate test samples at multiple DNA concentrations, similar
    to the concentrations in the procedure you recommend to users. You
    should include both wild-type and mutation sequences. In addition,
    the genotype of samples or sample panels you test should, as much as
    possible, reflect all the alleles that are included in the test.

-   Ensure that samples used in reproducibility testing are processed
    from "real" samples (e.g., whole blood, buccal swabs, or other
    intended use matrices) at the test site and that processing mimics
    the procedure you plan to recommend in the test labeling.

-   Include 3 or more sites with multiple operators at each site.
    Operators should reflect potential users of the assay, in terms of
    education and experience. If training will be necessary for users to
    perform the test once it is marketed, you should provide information
    on operator training. If such training is not expected to be
    provided for users, you should not provide additional training
    (other than the proposed labeling, such as the package insert) at
    the testing sites.

-   Ensure that procedures used in the reproducibility studies are the
    same as the procedure that you will recommend to users in the
    package insert.

-   Include multiple product lots, and multiple instruments (if
    instruments are part of the test system), to adequately test the
    expected performance of the system.

> In the study design description in your 510(k), you should identify
> which factors (e.g., instrument calibration, reagent lots, and
> operators) were held constant and which were varied during the
> evaluation, and describe the computations and statistical analyses
> used to evaluate the data.

# Method Comparison

You should perform method comparison studies that demonstrate that your
device detects the genotypes it claims to detect, and does not detect
mutations when none are present. Samples used in these studies should be
patient samples derived from the intended use population, in order to
show that the device will perform as claimed in a clinical setting. We
recommend that you perform method comparison studies at 3 or more sites
that reflect potential users of the assay, in terms of experience and
education.

Because of the abundance of technologies that could be used to genotype
a patient's drug metabolizing enzyme(s), assays may vary significantly
in terms of methodology, instrumentation, and sample source, making
direct comparison difficult. You should compare results of your device
to bidirectional DNA sequence analysis.

You should describe the protocol and results of your method comparison
in your 510(k). You should submit, along with your comparative sequence
data, a measure of sequence quality such as a phred score or percent
correct sequence calls. You can then use this information to calculate
the percent correct genotype calls of your device, relative to the
bidirectional sequence data. We recommend that you tabulate all results
and indicate the percent correct calls for the various genotypes. We
recommend that you resolve and explain all discrepant results in the
510(k); however, you should use original unresolved results for all
performance calculations, in order to avoid bias. You should include
failed assays (e.g., inability to correctly determine genotype within a
sample, reporting of an incorrect result, instrument failure, or reagent
failure) in your description of results. Any incorrect or absent
genotype determinations should be considered disagreements for the
purposes of reporting performance characteristics.

## Clinical Validation

Prospective clinical testing to determine clinical validity may not be
necessary for validation of DME genotyping systems, if there is an
established scientific framework and sufficient body of evidence
supporting the clinical validity and utility of your device. In this
case, you should provide the relevant peer-reviewed references. These
should include multiple studies that test appropriate populations. In
cases where the literature does not sufficiently support your
indications for use, you should conduct studies (usually prospective
studies) to support claims for your device. In either case, you should
demonstrate the association between the drug metabolizing enzyme
genotype and the drug metabolic profile based on clinical testing (such
as enzymatic rate studies) of study subjects.

## 

## Study Samples

While prospective samples are preferred, well-characterized samples from
banks can be used in your method comparison study, if clinical utility
and validity are already established in the literature. You should use
clinical samples from all matrices you claim in your intended use to
demonstrate that correct results can be obtained from clinical material.
You should fully describe selection (inclusion/exclusion) criteria and
characterize any relevant features of the samples (whether prospective,
or from banks). You should also provide clear information supporting
sample integrity.

Appropriate sample size depends on factors such as reproducibility,
interference, and other performance characteristics of the test.  We
recommend that you provide a statistical justification to support your
study sample size.

We recommend that you evaluate test samples that encompass all genotypes
in the test system. For rare mutant alleles, genomic DNA samples or
clone blends may also be used, but the composition of the test samples
generated from these clones should resemble, as closely as possible, the
protein and DNA content and concentrations of real clinical samples. If
you use clones, you should test them in combination with various other
alleles or genetic backgrounds, so that they reflect heterozygous, as
well as homozygous samples. In cases where you cannot obtain multiple
samples of a rare genotype, you should test a statistically determined
number of replicates so that you can calculate a meaningful
reproducibility value for that allele.

[]{#__RefHeading___Toc91398894 .anchor}

## Sample collection and handling conditions

We recommend that you validate statements in your labeling about sample
storage and transport by assessing sample stability and recovery over
the storage times and temperatures recommended to users.  For example,
an appropriate study may include an analysis of aliquots stored under
the conditions of time, temperature, or specified number of freeze/thaw
cycles.  We recommend that you state your acceptance criteria for the
sample stability parameters.

# Software

If your system includes software, you should submit software
documentation detailed in accordance with the level of concern (See:
*Guidance for the Content of Premarket Submissions for Software
Contained in Medical Devices* (http://www.fda.gov/cdrh/ode/57.html)).
You should determine the Level of Concern prior to the mitigation of
hazards. In vitro diagnostic devices of this type are typically
considered a moderate level of concern, because software flaws could
indirectly affect the patient and potentially result in injury because
of the action or inaction of a healthcare provider who does not get
accurate information.

You should include the following points, as appropriate, in preparing
software documentation for FDA review:

-   Full description of the software design. Your software should not
    include utilities that are specifically designed to support uses
    beyond those in your intended use. You should also consider privacy
    and security issues in your design. Information about some of these
    issues may be found at the following website regarding the Health
    Insurance Portability and Accountability Act (HIPAA)
    http://aspe.os.dhhs.gov/admnsimp.

-   Hazard analysis based on critical thinking about the device design
    and the impact of any failure of subsystem components, such as
    signal detection and analysis, data storage, system communications
    and cybersecurity in relationship to incorrect patient reports,
    instrument failures, and operator safety.

-   Documentation of complete verification and validation (V&V)
    activities for the version of software that will be submitted to
    demonstrate substantial equivalence. You should also submit
    information regarding validation of the compatibility of assay
    software with any instrumentation software.

-   If the information you include in the 510(k) is based on a version
    other than the release version, identification of all differences in
    the 510(k) and detail how these differences (including any
    unresolved anomalies) impact the safety and effectiveness of the
    device.

Below are additional references to help you develop and maintain your
device under good software life cycle practices consistent with FDA
regulations.

-   General Principles of Software Validation; Final Guidance for
    Industry and FDA Staff; available on the FDA Web site at:
    http://www.fda.gov/cdrh/ode/510kmod.pdf.

-   Guidance for Off-the-Shelf Software Use in Medical Devices; Final;
    available on the FDA Web site at:
    http://www.fda.gov/cdrh/ode/guidance/585.pdf.

-   21 CFR 820.30 Subpart C -- Design Controls of the Quality System
    Regulation.

-   ISO 14971-1; Medical devices - Risk management - Part 1: Application
    of risk analysis.

-   AAMI SW68:2001; Medical device software - Software life cycle
    processes.

# Labeling

The premarket notification should include labeling in sufficient detail
to satisfy the requirements of 21 CFR 807.87(e).  The following
suggestions are aimed at assisting you in preparing labeling that
satisfies the requirements of 21 CFR 807.87(e). Although final labeling
is not required for 510(k) clearance, final labeling for in vitro
diagnostic devices must comply with the requirements of 21 CFR 809.10
before an *in vitro* diagnostic device is introduced into interstate
commerce.

> **Directions for use**
>
> You should present clear and concise instructions that delineate the
> technological features of the specific device and how the device is to
> be used.  Instructions should encourage local/institutional training
> programs, if available, that are designed to familiarize users with
> the features of the device and how to use it in a safe and effective
> manner.
>
> If you do not intend to provide reagents for DNA extraction and
> preparation as part of the assay, you should provide specifications
> for reagents needed and for assessing the quality of the assay input
> DNA, so that the user can select appropriate reagents.
>
> **Interpretation of Results**
>
> You should clearly define any phenotype definitions (e.g., Extensive,
> Intermediate, Poor, or Ultrarapid Metabolizers in the case of
> cytochrome P4502D6). We recommend that you provide a section in your
> package insert to aid users in interpreting test results. The results
> should be consistent with current recommendations of genetics
> professional societies, if applicable, and should contain adequate
> interpretation guidelines for the use of the ordering physician. See
> Test Results in Section 6. Where applicable, reports should describe
> the polymorphisms identified by your test and the methodology and
> technology used for detection.  You should identify representative
> literature references describing genotypic interpretations, or
> phenotypic predictions, if applicable, to enable users to access
> information about specific genotypes.
>
> **Expected Values**
>
> You should provide data concerning prevalence for specific alleles,
> including, where appropriate, allele prevalence according to ethnicity
> and race.
>
> **Quality Control**
>
> You should include a description of quality control recommendations in
> the package insert. This should include a clear explanation of what
> controls are to be used in the assay and the expected results for the
> control material.
>
> **Precautions for interpretations**
>
> You should clearly describe any assay limitations in the labeling.
> Most drug metabolizing enzyme genotyping systems should contain the
> following limitations:

-   Results provided by this type of genetic test should only be used to
    supplement other tools for therapeutic decision-making in
    conjunction with routine monitoring by a physician.

-   The effect that a specific DME allele has on drug metabolism may
    vary depending on the specific drug, even for drugs within a
    specific class. Effects of specific alleles on drug metabolism are
    well-documented for some drugs; for other drugs, they are less
    well-documented. Therefore, clinicians should use professional
    judgment when interpreting results from this type of test.

-   Results from this type of assay should not be used to predict a
    patient's response to drugs in cases where either 1) the drug
    metabolizing enzyme activity of the allele has not been determined,
    or 2) the drug's metabolic pathway has not been clearly established.

> **Performance Characteristics**
>
> You should include in the package insert all study designs and results
> for studies described in Sections 7 and 8 of this guidance document
> that would aid users in interpreting test results. For the method
> comparison, you should describe device performance in comparison to a
> gold standard method, such as bi-directional DNA sequencing. We
> recommend that you present results in the form of tables (e.g., n x n
> tables), descriptions of percent correct genotype calls relative to
> sequence analysis, and a list of the nature of any miscalls (e.g.,
> correct sequence versus one predicted by device). We recommend that
> you present results for specific genotypes, in addition to overall
> results.

[^1]: <http://www.fda.gov/cdrh/ode/parad510.html>

[^2]: Refer to
    [http://www.fda.gov/cdrh/ode/indicate.html](http://www.fda.gov/cdrh/ode/indicate.pdf)
    for the recommended format.

[^3]: If FDA makes a substantial equivalence determination based on
    acceptance criteria, the subject device should be tested and shown
    to meet these acceptance criteria before being introduced into
    interstate commerce. If the finished device does not meet the
    acceptance criteria and, thus, differs from the device described in
    the cleared 510(k), FDA recommends that submitters apply the same
    criteria used to assess modifications to legally marketed devices
    (21 CFR 807.81(a)(3)) to determine whether marketing of the finished
    device requires clearance of a new 510(k).

[^4]: See Required Elements for a Declaration of Conformity to a
    Recognized Standard (Screening Checklist for All Premarket
    Notification \[510(K)\] Submissions),
    <http://www.fda.gov/cdrh/ode/reqrecstand.html>.

[^5]: Some of the elements listed in this section are applicable to
    instrumentation. If you are submitting a separate 510(k) for your
    instrumentation, you can describe the elements specific for
    instrumentation in that 510(k).