Comparative analysis of allowable total error specifications for coagulation factor assays utilizing China National External quality assessment scheme data and biological variation data

Background: It is necessary and challenging to establish reasonable and feasible total error specifications for coagulation factor assays for quality control and assessment. The aim of this study is to establish new total error specifications for coagulation factor assays by combining External Quality Assessment data with reliable biological variation data.

Methods: Data from China National External Quality Assessment Scheme (28,408 results from 1,381 laboratories) were analyzed, stratifying External Quality Assessment data by reference intervals to establish concentration-dependent total error specifications. A "state-of-the-art" total error was defined at 80% best results of the participants. Then these specifications were compared with biological variation-derived total error to determine recommended total error specifications for different concentration levels.

Results: None of the measurands could meet biological variation-derived optimum total error. Eight parameters (FII, FVIII, FX at both high and low levels; FVII and FIX at high level) reached the desirable criteria. Only FXI at low level can't met the minimum criteria.

Conclusions: The establishment of total error specifications for coagulation factor assays should be set separately according to different concentration levels and attainability of current testing technologies. Setting total error specifications should also consider clinical requirements and regulatory standards across different regions. Analyte concentration significantly influences laboratory performance, particularly for low-concentration coagulation factors. Total error specifications need updated periodically in the further.

Abbreviations: Tea, allowable total error; BV, biological variation; SOTA, state of the art; EQAS, External quality assessment schemes; ME, measurement error; RIs, reference intervals; BIVAC, Biological Variation Data Critical Appraisal Checklist; QIs, quality items; EFLM, European Federation of Clinical Chemistry and Laboratory Medicine; APS, analytical quality specifications; ISO, International Organization for Standardization; EQA, External quality assessment; PT, proficiency testing; RCPA, Royal College of Pathologists of Australasia; RfB, Reference Institute for Bioanalytics; ECAT, External Quality Control for Assays and Tests.