The application of quality specifications derived from biological variation in routine chemistry external quality assessment and internal quality control

Abstract

Objective To discuss the application of allowable total error (TEa) and allowable imprecision derived from biological variation in routine chemistry external quality assessment (EQA) and internal quality control (IQC) and set up quality specifications of routine chemistry in our country. Methods Data of test items including K，Na，CI，Ca，P，Glu，Urea，UA，Cre，Alb，TP，TC，TG，AST，ALT，TBil，ALP，AMY，CK，LDH，Fe，Mg，Cu，Zn and GGT was collected and evaluated by a nationwide EQA. At the same time the coefficients of variation (CVs) of these test items during the month were acquired from the IQC reports of each laboratory and then the results were analyzed. Results Percent of pass was different in these test items based on TEa derived from biological variation in EQA results.Except for items of CI，Mg，Cu and Zn, about 80% of participant laboratories could achieve the minimum performance of biological variation.About 80% of participant laboratories could achieve the desired performance of biological variation for K，P，Glu，Urea，UA，Cre，TC，TG，ALT，AST，TBil，AMY，CK，LDH，Fe and GGT.About 80% of participant laboratories could achieve the optimum performance of biological variation for Urea，UA，TC，TG，ALT，AST，TBil，CK，and GGT.And the IQC results showed that acceptable percents of different items based on three allowable imprecision were different. More than 80% of participant laboratories could achieve the minimum allowable imprecision for K，P，Glu，Urea，UA，TC，TG，ALT，AST，TBil，AMY，CK，LDH，DBil，Fe，GGT , the desirable imprecision for P，Urea，UA，TG，ALT，AST，TBil，CK，DBil，Fe，GGT and the optimum imprecision for TG，ALT，CK，DBil，Fe. Conclusions The quality specifications derived from biological variation can be as evaluation criteria for EQA and IQC in order to know the detection ability of each laboratory more completely and objectively, set up quality specifications derived from allowable total error and allowable imprecision in routine chemistry and to provide basis for mutual recognition of routine chemistry test results.（Chin J Lab Med，2012,35：531-537） Key words: Clinical chemistry tests; Reference values; Quality control