Guideline References

Interference Testing in Clinical Chemistry — 3rd Edition

The primary standard governing interference evaluation. EP07 describes procedures to screen potential interferents (paired-difference experiment), quantify interference effects (dose-response experiment), and confirm interference in patient samples. It specifies experimental designs, replicate requirements, statistical analysis methods, and acceptance criteria for both manufacturer characterization and laboratory verification studies.

Interference Testing — Supplemental Tables of Interferent Test Concentrations

The companion supplement to EP07. EP37 provides tables of recommended test concentrations for specific potential interferents by analyte category. Use EP37 to determine appropriate interferent concentrations when designing interference studies for specific measurands.

Accreditation and Regulatory Requirements

CAP and CLIA require documentation of interference testing as part of method verification. Records must include the interferents tested, concentrations used, measurand levels evaluated, statistical analysis, and pass/fail determination relative to the defined allowable difference.