CMS SOM App. C, Tag D5423

specifications.

(b)(2) Establishment of performance specifications. Each laboratory that modifies

an FDA-cleared or approved test system, or introduces a test system not subject to

FDA clearance or approval (including methods developed in-house and

standardized methods such as textbook procedures), or uses a test system in which

performance specifications are not provided by the manufacturer must, before

reporting patient test results, establish for each test system the performance

specifications for the following performance characteristics, as applicable:

Interpretive Guidelines §493.1253(b)(2)

Prior to reporting patient test results, the laboratory is responsible for establishing the

performance specifications for each modified FDA-cleared or approved test system, each

test system not subject to FDA clearance or approval, and each test system for which the

manufacturer does not provide performance specifications. The establishment of method

performance specifications should provide evidence that the accuracy, precision,

analytical sensitivity, and analytical specificity of the procedure is adequate to meet the

clients’ needs as determined by the laboratory director and clinical consultant.

“Modified by the laboratory” means any change to the assay that could affect its

performance specifications for sensitivity, specificity, accuracy, or precision, etc.

Laboratory modification of the manufacturer’s instructions that could affect performance

specifications include but are not limited to:

• Change in specimen handling instructions;

• Change in incubation times or temperatures;

• Change in dilution of specimen or reagent;

• Using a different calibration material or reference material, or changing the

manufacturer’s set-points;

• Introducing a different antibody (source, monoclonal-vs.-polyclonal);

• Change or elimination of a procedural step;

• Change or addition of detector (conjugate) or substrate;

• Change in the solid phase;

• Change in the cutoff or method of calculating the cutoff for semi-quantitative

assays;

• Change in the endpoint or calculation of the endpoint;

• Addition of adsorbent; and

• Change in the strain of antigen in serologic assays.

A modified moderate complexity test (including modifications in its intended use) is

considered uncategorized for CLIA and therefore becomes a high complexity test.

EXCEPTIONS: Use of a manufacturer’s reagents that are exempt from the premarket

notification procedures in 21 CFR §807 for an instrument produced by another

manufacturer is not considered a method modification. If the FDA has cleared a

manufacturer’s reagents and/or calibration materials for use with an instrument produced

by another manufacturer, the use of these reagents/materials is not considered a method

modification and does not require establishment of performance specifications.

However, the laboratory must verify performance specifications as required under

§493.1253(b)(1). Reverification of performance specifications is required if reagents are

changed to those of another manufacturer.

“Modified by the laboratory” also means any change in intended use that could affect

test system performance specifications for sensitivity, specificity, accuracy, and

precision, etc., and the clinical utility of the test system. Changes in intended use are

considered “off-label” use of a commercial test system. CAUTION: “Off-label” use is

not supported by the manufacturer’s clinical data.

Examples of changes in intended use are:

• Using a different sample matrix (plasma vs. urine);

• Using or promoting the test for another purpose (screening vs. diagnostic); and

• Changing the type of analysis (qualitative results reported as quantitative).

NOTE: The laboratory is responsible for establishing performance specifications for test

systems using analyte specific reagents (ASR).

For automated or semi-automated analyzers, the use of reprocessed (reconditioned)

rotors/cuvettes which have passed quality control inspection criteria of the reprocessing

company, are not considered a method modification if/when they are returned to the same

laboratory that sent them for cleaning and re-use.

Specimens of known quantitative value may be used to determine the laboratory’s

performance specifications for a qualitative test.

Each laboratory is responsible for determining that its performance specifications for

each test method are not affected by the relocation of the laboratory or test system. (See

manufacturer’s package insert regarding critical requirements such as set-up, limitations,

environmental conditions, etc.)

If calibration material is used to establish method performance specifications, the

laboratory must demonstrate that there is a minimal matrix effect and the calibration

material is appropriate for establishing test system performance specifications.

If the LIS performs any calculations to determine a laboratory result, the calculations

must be verified immediately after the LIS is programmed and prior to initial calculation

of patient results.

NOTE: Public health testing performed on environmental (non-human) samples is not

subject to CLIA.

Probes §493.1253(b)(2)

How does the laboratory determine if a new or revised LIS program (whether purchased

or developed in-house) performs acceptably before it is integrated into routine operation?

§493.1253 Standard: Establishment and verification of performance

specifications.

(b)(2)(i) Accuracy.

Interpretive Guidelines §493.1253(b)(2)(i)

Accuracy - The laboratory is responsible for establishing that the method produces

correct results. Establishment of accuracy may be accomplished by:

• Testing reference materials or comparing results of tests performed using an

established reference method; or

• Comparing split sample results with results obtained from another method, which

has already been shown to provide accurate results.

For qualitative methods, the laboratory is responsible for establishing that a method will

identify the presence/absence of the analyte.

In establishing a test system for a new analyte, research results may be used to document

the accuracy of the test by correlation with the clinical presentation. In addition, the

laboratory needs to determine the test system’s precision and have mechanisms for

determining analytical specificity, analytical sensitivity, and interfering substances.

§493.1253 Standard: Establishment and verification of performance

specifications.

(b)(2)(ii) Precision.

Interpretive Guidelines §493.1253(b)(2)(ii)

Precision (Reproducibility) - The laboratory is responsible for establishing the precision

of each test system by assessing day-to-day, run-to-run, and within-run variation, as well

as operator variance.

This may be accomplished by:

• Repeat testing of known patient samples over time;

• Testing QC material in duplicate and over time; or

• Repeat testing of calibration materials over time.

EXCEPTION: For fully automated systems that are not user dependent, operator

variance does not need to be evaluated.

§493.1253 Standard: Establishment and verification of performance

specifications.

(b)(2)(iii) Analytical sensitivity.

Interpretive Guidelines §493.1253(b)(2)(iii)

Analytical Sensitivity - The laboratory is responsible for determining the lowest

concentration or amount of the analyte or substance that can be measured or

distinguished from a blank, i.e., minimum detection limits or how much of the analyte

must be present to be measured.

For modified test systems, the laboratory may use the lower limit of the manufacturer’s

reportable range if it has demonstrated that the modification has not affected the lower

limit.

§493.1253 Standard: Establishment and verification of performance

specifications.

(b)(2)(iv) Analytical specificity to include interfering substances.

Interpretive Guidelines §493.1253(b)(2)(iv)

Analytical Specificity - The laboratory must determine the extent to which the method

measures the analyte for which it is reporting results.

Interfering Substances - The laboratory must document information regarding

interfering substances from product information, literature, or its own testing. These may

include: specimen hemolysis, anticoagulant, lipemia, and turbidity; patients’ clinical

conditions, disease states, and medications.

§493.1253 Standard: Establishment and verification of performance

specifications.

(b)(2)(v) Reportable range of test results for the test system.

Interpretive Guidelines §493.1253(b)(2)(v)

Reportable Range- The laboratory is responsible for establishing the upper and lower

limits of the test system.

§493.1253 Standard: Establishment and verification of performance

specifications.

(b)(2)(vi) Reference intervals (normal values).

Interpretive Guidelines §493.1253(b)(2)(vi)

Reference Range (Normal Values) - The laboratory must establish a reference range

that is appropriate for the laboratory’s patient population (i.e., a normal range that reflects

the type of specimen and demographic variables such as age and sex, as applicable).

§493.1253 Standard: Establishment and verification of performance

specifications.

(b)(2)(vii) Any other performance characteristic required for test performance.