Guideline References

Evaluation of Precision of Quantitative Measurement Procedures

The primary standard governing extended (long-term) precision study design. EP05-A3 specifies the 20 × 2 × 2 protocol (20 days, 2 runs per day, 2 replicates per run) and recommends ANOVA-based analysis to separate within-run, between-run, between-day, and within-laboratory variance components.

User Verification of Precision and Estimation of Bias

Specifies a short-term multi-day protocol — typically 5 × 1 × 5 (5 days minimum, 1 run per day, 5 replicates per run) — which yields the minimum degrees of freedom required for a statistically sound assessment of within-run and within-laboratory precision against published claims.

Standard: Establishment and Verification of Method Performance Specifications

For non-waived tests, CLIA requires that laboratories verify precision (and other performance characteristics) for FDA-cleared tests, and establish precision data for laboratory-developed tests.