European Specifications for Imprecision and Inaccuracy Compared with Operating Specifications That Assure the Quality Required by US CLIA Proilciency-Testing Criteria

Proposed and interim European quality specificationsfor imprecisionand inaccuracy have been compared with the US CUA total error criteria for proficiencytesting (PT). To assess the relative demands of separate imprecisionand inaccuracy specificationsvs total error criteria, we derived the imprecisionand inaccuracythat would be allowable if a testing process were to provide 90 % assurance of achieving the analytical quality required by CLIA PT cri-teria. Charts of operating specifications (OPSpecs charts) were prepared for commonly used single-rule and multi-rule quality control procedures with 2 and 4 control mea-surements per run. Of the 23 tests studied, the proposed European specifications for imprecision and inaccuracy were more demanding than the CLIA requirementsfor 12 tests (albumin, alkaline phosphatase, amylase, calcium