European specifications for imprecision and inaccuracy compared with operating specifications that assure the quality required by US CLIA proficiency-testing criteria

Abstract

Proposed and interim European quality specifications for imprecision and inaccuracy have been compared with the US CLIA total error criteria for proficiency testing (PT). To assess the relative demands of separate imprecision and inaccuracy specifications vs total error criteria, we derived the imprecision and inaccuracy that would be allowable if a testing process were to provide 90% assurance of achieving the analytical quality required by CLIA PT criteria. Charts of operating specifications (OPSpecs charts) were prepared for commonly used single-rule and multi-rule quality control procedures with 2 and 4 control measurements per run. Of the 23 tests studied, the proposed European specifications for imprecision and inaccuracy were more demanding than the CLIA requirements for 12 tests (albumin, alkaline phosphatase, amylase, calcium, chloride, creatinine, lactate dehydrogenase, lithium, magnesium, total protein, sodium, and thyroxine). The CLIA total error criteria were more demanding than the proposed European specifications for nine tests (alanine aminotransferase, aspartate aminotransferase, total bilirubin, cholesterol, creatine kinase, iron, triglycerides, uric acid, and urea nitrogen). Two tests (glucose, potassium) showed different requirements at different decision levels. Manufacturers and laboratory analysts need to compare these different quality specifications on a test-by-test basis to guide the development, selection, evaluation, and control of laboratory measurement procedures.

Could light meal jeopardize laboratory coagulation tests?

“…The concentration of triglycerides in our samples was lower than 2.0 mmol/L. Obviously the quality specifications derived from biological variation ( 17 ) are considered both very important and useful in the daily practice by the quality managers of the medical laboratories ( 16 , 18 ). Moreover, Nikolac et al .…”

“…The level of statistical significance was set at P < 0.05. The clinically significant change in consecutive results from an individual, taking into consideration both analytical and biological variations, was calculated for each test using the reference change value (RCV) equation as follows: where: Z is a constant depending on the probability, where 1.96 is most often used as significant, that is, P < 0.05; CV w is the within-subject biological variation obtained from Westgard database ( 16 ); and CV a is the analytical coefficient of variation from our internal quality control. Mean % differences were determined according to the formula: …”

“…Only mean % differences higher than RCV were considered clinically significant. Desirable specification for imprecision (DSI) derived from biologic variation ( 16 ) was used as our criteria of acceptance in lipemia analytical interference testing.…”

Large Academic Hospital Laboratory Investigates a Major Pre-Analytical Challenge in Africa and Developing Countries

“…(b) To determine acceptable imprecision based on the intra-individual biological variation. The value of ≤0.5CVb was described [22,[24][25][26] and this value was used for each analyte. The biological variation was obtained from the European Federation Clinical Chemistry and Laboratory Medicine (EFLM) database.…”

Development and Application of a Laboratory-Developed Quality Control Program for Blood Glucose Monitoring Systems: A Single Institute Experience

“…The meangrand was always considered a target value regardless of the lot, even when more than two lots of control material were used. Desirable specification of the TE due to biological variation for plasma glucose of 5.5% was used as the allowable total error (TEa) to calculate the sigma-metric [ 2 ].…”