CLIA Testing Procedures & Method Validation 4

Question 1

A technologist performing a glucose assay obtains QC results of 98 mg/dL and 102 mg/dL for a control with a mean of 100 mg/dL and SD of 3 mg/dL. Which Westgard rule applies?

Accepted Answer

Within acceptable limits — no rule violated

Answer

Both values fall within ±2 SD of the mean (±6 mg/dL), so no Westgard warning or rejection rule is triggered.

Question 2

What is 'carryover' in the context of analytical testing, and why is it evaluated during method validation?

Accepted Answer

The transfer of analyte from a high-concentration sample to a subsequent low-concentration sample, potentially causing falsely elevated results

Answer

Carryover occurs when residual analyte from a previous high-concentration sample contaminates the next sample, and it must be evaluated to prevent false results.

Question 3

Which parameter best describes a method's ability to detect small differences in analyte concentration between two samples?

Accepted Answer

Analytical sensitivity

Answer

Analytical sensitivity refers to the ability of a method to detect small changes in analyte concentration, often expressed as the slope of the calibration curve.

Question 4

When validating a laboratory-developed test (LDT) for a high-complexity analyte, which performance characteristic is NOT required by CLIA to be established?

Accepted Answer

Cost per test

Answer

CLIA mandates validation of accuracy, precision, reportable range, reference intervals, and interferences, but cost per test is a business consideration, not a regulatory requirement.

Question 5

A laboratory is validating a new serum creatinine method. Specimens with creatinine >10 mg/dL are routinely diluted 1:5. The laboratory must verify that:

Accepted Answer

The dilution protocol does not alter the matrix significantly and diluted results are accurate

Answer

When dilution extends the reportable range, the laboratory must verify that the dilution protocol maintains accuracy and does not introduce matrix-dependent errors.

(CLIA) Clinical Laboratory Improvement Amendments Certification Practice Test

(CLIA) Clinical Laboratory Improvement Amendments Certification Practice Test

CLIA Testing Procedures & Method Validation 4