ABSTRACT
Objective To summarize and review the comparative results of the isotope dilution mass spectrometry in Cholesterol Reference Method Laboratory Network (CRMLN)project of the Centers for Disease Control and Prevention (CDC)of the United States in order to provide quality controls for determination of blood lipid.Methods The isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS)methods for determination of serum total cholesterol (TC)and triglycerides (TG)were developed to participate in the comparison of CRMLN.The survey was conducted every three months before 2016 and every half year from 2016.Four kinds of reference materials with two parallel tubes for each material and each tube in duplicate were determined in every survey.At least two certified reference materials used as quality control samples were analyzed simultaneously in each determination.Results In the 15 comparisons the CV of the TC determination method in our laboratory was 0.43％ while the CV of all the participated laboratories in CRMLN was 0.42％.The bias from the overall mean value in our laboratory was 0.22％ while the bias from the CDC target values was 0.58％.The CV of the TG determination method in 15 tests of our laboratory was 0.62％ and the bias was-0.98％ from the overall mean value and-0.80％ from the target values of CDC.Among the 60 results for comparison,98％ (59/60)of CV in the TC determination met with CDC requirement for precision (CV≤ 1％),and 70％ of bias (42/60) of the results met with CDC requirement for accuracy (bias ≤ 1％).For the 60 results in comparison of TG determination,92％ (55/60)of bias of the results met with the accuracy requirement of CDC (bias ≤2.55％).Conclusion In CRMLN comparison the results of TC and TG determined by ID-LC/MS/MS method were consistent with the values which were certified by CDC and determined by other network laboratories.The comparative surveys may play an important role in the standardization of lipid determination,and should be expected to provide experiences and technical supports in the comparative plan for reference measurement in our country.
ABSTRACT
Objective To investigate the reasons of unacceptable results and corrective measures adopted in external quality assessment (EQA)for blood gas and acid-base analysis.Methods The reasons of unacceptable results and corrective measures for three EQA testing events of blood gas and acid-base analysis in 2016 were reported through EQA system based on web which was developed by National Central for Clinical Laboratories.The responses were divided into seven major groups,including EQA samples,errors in reporting results,methodology,equipments,techniques,EQA evaluations and unexplainable results after survey.Results The disqualified rates of EQA survey on blood gas and acid-base analysis were ranged from 0.5％ to 13.1％ and reporting rates of disqualification causes were ranged from 45.8％ to 69.0％ (except for the groups less than 20 laboratories).In the reasons for unacceptable results technological defects (35.9％ to 37.0％)were mainly associated with inappropriate specimen handling and/or storing,reagents and calibration problems.The defects of equipments (24.4％ to 27.9％) included mainly the malfunction and failure to adhere to scheduled instrument maintenance procedures.The errors in reporting results (12.2％ to 19.7％) were mostly transcription errors and reporting wrong codes.The unexplainable results after survey account for 8.7％ to 9.6％.The methodological defects (8.1％ to 11.8％) were largely attributed to inadequate training and quality control method.The defects of EQA evaluations (0.8％ to 3.3％)were all due to inappropriate grouping.The categorizations of the problems in the three EQA testing events were similar.The most corrective measures were appropriate,in which re-education and training for staff and improvement in instruments,reagents,internal quality control,calibration and process of reporting results were included.Conclusion The analysis and classification for reasons of unacceptable EQA results should be helpful for laboratories in identifying opportunities for improvement and adopting corrective measures in time.