ABSTRACT
Objective To evaluate the homogeneity of the proficiency test samples to verify whether it meets the requirements of the comparison in international reference laboratory.Methods According to the Guidance on Evaluating the Homogeneity and Stability of Samples Used for Proficiency Testing (CNAS-GL03),14 biochemical indexes including ALT,AST,ALP,GGT,CK,LDH,TP,T-Bil,Urea,Cr,UA,Glu,TG and TC in the past three years (from 2014 to 2016)were tested by the Roche detection system Modular P800 Biochemical analyzer.The mean ((x)),standard deviation (s)and coefficient of variation (CV)of the samples were calculated.One-way analysis of variance (ANOVA)was performed and the guideline of Ss ≤0.3σ was used to evaluate the between-bottle differences.Results The results showed that the CVs of AST in RELA 2014A and B were higher than 2.0％.The CVs of CK were over 2％ in all tests except for RELA 2016B.The results of ANOVA for RELA samples demonstrated that the F value of CK was over the critical value 4.39,which was statistically significant (P ＜ 0.05).The F values of the ALT and T-Bil in 2015B and the Cr in 2014A were also over 4.39 (P ＜ 0.05) respectively,while the F values of other measurements were less than the critical value of F,indicating there was no statistical significance (P ＞ 0.05).The CK measurement data Ss ＞ 0.3σ in all the samples by the guideline of Ss ≤ 0.3σ,suggesting that there was a between-bottle difference in CK.The other indexes were Ss ≤ 0.3σ,showing no between-bottle difference in those items.Conclusion There were significant differences between the bottles of the CK item in the past three years,and the homogeneity of all the other items in the samples could meet the requirements of Proficiency Testing for the international reference laboratory.