Guideline References

Evaluation of Linearity of Quantitative Measurement Procedures

The primary standard governing linearity study design, analysis, and interpretation for both manufacturers (validation) and end-user laboratories (verification). EP06-Ed2 recommends a minimum of five concentration levels tested in duplicate, spanning the claimed linearity interval. Analysis uses weighted least squares (WLS) regression — or OLS when repeatability is concentration independent — with deviations from the fitted line evaluated against the allowable deviation from linearity (ADL). The second edition introduced concentration-level-specific acceptance criteria in place of the global polynomial approach used in EP06-A.

Standard: Establishment and Verification of Method Performance Specifications

CLIA requires that laboratories verify or establish method performance specifications — including the reportable range of patient test results — for all non-waived tests before reporting patient results. Linearity verification across the analytical measurement range is the standard method for establishing this reportable range.