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Objective To review the performance of the IFCC enzyme reference methods in China laboratories and to evaluate the competence of enzyme reference measurement in China.Methods The Intemational Federation of Clinical Chemistry and Laboratory Medicine(IFCC)enzyme reference methods were performed in 8 China laboratories.Reference procedures were developed by each laboratory and the performances were evaluated.The Clinical and Laboratory Stadards Institute(CLSI)EP-5 protocol was used for the evaluation of precision and certified reference materials(CRMS)were used for the verification of trueness.Seven of the 8 laboratories participated in the 2006 IFCC external quality assessment program for reference laboratories(RELA)for the assessment of the measurement performance.Results Within-run CVs of less than 1.5%and between-run CVs of less than 2%were achieved bv all the China laboratories.Results on CRMs by some of the laboratories agreed with the certified value within the stated uncertainty.In the 2006 RELA,the averages and the interlaboratory CVs of the China laboratories were similar to those of international laboratories.Conclusion A preliminary enzyme reference method laboratory network has been established in China.
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Objective To establish reference methods for the measurement of catalytic activity concentrations of enzymes at 37℃ which have been published by IFCC and evaluate accuracy of reference methods.Methods Six reference methods for the measurement of catalytic activity of enzymes were established with two sets of apparatus systems of PE and Agilent according to International Federation of Clinical Chemistry(IFCC)37℃ reference procedures in two reference labs respectively.The commercial Roche calibrator c.f.a.s was used to monitor the precision of two reference labs as quality control material.Certified Reference Materials(CRMs)represented an efficient tool to assess the analytic performance for the verification of trueness and in two labs.The measurement accuracy of the assays for catalytic activity concentrations of 6 enzymes [alanine aminotransferase(ALT),aspartate aminotransferase(AST),lactate dehydrogenase(LDH),creatine kinase(CK),gamma-glutamyhransferase(GGT),amylase(AMY)]was further verified and validated by international ring trial program.Results The within-laboratory variations of 6 enzymes in both of the reference lab were ranged from 0.5%-1.9%.Their results showed fully agreement with deviation less than 2.1%.The value of CRM was in the tolerant limit and analytic accuracy was verified.The results of four enzymes(ALT,AST,GGT,AMY)lay within (x)±s.However,the result of CK and LDH lay within (x)±2s.Except sample A for the LDH testing,we did not find any deviation variable in the detection of other enzymes.Conclusions The reference methods for the measurement of catalytic activity of enzymes(ALT,AST,LDH,CK,GGT,AMY)at 37℃ in the two labs by use of two sets of apparatus systems of PE and Agilent have been established and these methods showed excellent stability and accuracy.
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Objective To prepare in-house calibrator of apolipoprotein A1 and apolipoprotein B with the values are traceable to the WHO-International reference materials SP1-01 and SP3-07.Methods We participated in the Northwest lipid research laboratory (NWLRL) protocol for target value transfer of WHO-IFCC apo A1 and apoB reference materials, and evaluated of comparability of the measurement.The analyses were performed on a Olympus AU 400, apo A1 and apoB were determined by immunoturbidimetric endpoint method.Results Through 3-step study, the precision and accuracy of apo A1 and apoB determination of our company met the NWLRL criteria.Correlation coefficients between obtained and assigned values of NWLRL on 40 individual serum samples were 0.983 for apo A1, 0.987 for apoB, the average absolute bias were 2.7 % for apo A1, 3.0 % for apoB, respectively.Conclusion NWLRL issued the certificate to Zhongsheng Beikong Bio-Technology and Science Inc.for the in-house apo A1 and apoB calibrator values are traceable to the WHO- International reference materials.