ABSTRACT
Objective@#To evaluate the external quality assessment (EQA) program for genotyping results of tacrolimus metabolism-related cytochrome P450 family 3 subfamily A member 5 ( CYP3A5 )using plasmid DNA constructed in vitro as quality control samples, discuss the problems in clinical laboratories enrolled in the program and improve the detection quality of CYP3A5 gene. @*Methods@#Recombinant plasmid carrying CYP3A5 *3 (rs776746) AA locus sequence was constructed as wild type sample and plasmid with CYP3A5 *3 GG mutation as mutant type sample. Heterozygous mutant samples were obtained by mixing the two plasmids with equal proportion. Recombinant plasmids DNA were used as the sample panel for EQA scheme. Participating laboratories were asked to test the samples using their routine methods and report the results before deadlines. The scores of each laboratory were calculated based on their results and the overall coincidence of different samples as well as the sensitivity and specificity of different methods. @*Results@#CYP3A5 *3 locus genotypes of the constructed plasmid were verified by Sanger sequencing. The results of 15 and 17 valid laboratories were received respectively in the two EQA programs. The total percentage of 93.33% (14/15) and 100% (17/17) of the laboratories submitted correct results for all the samples. The overall coincidence rates were 96% (72/75) and 100% (85/85) respectively. All the laboratories using digital FISH got full marks in two EQA schemes, while the coincidence rates were 90% (27/30) and 100% (40/40) for Sanger sequencing. @*Conclusion@#The recombinant plasmid DNA constructed in this study could effectively detect the performance of reagents with good clinical applicability. The results of EQA programs suggested that the overall accuracy rate of enrolled laboratories was high enough, while the performances in some laboratories still need to be improved. Quality controls in clinical laboratories were essential to assure the accuracy of results.