| Objective:Tacrolimus is the most widely used immunosuppresant in solid organ transplant patient.The cytochrome P450 3A5(CYP3A5)has been proved to be assosiated with tacrolimus dose requirement.Molecular testing for CYP3A5 genotyping is required for the optimization of treatment of tacrolimus.In order to determine the performance of laboratories with regard to the testing process for CYP3A5 to ensure the consistency and accuracy of the test results,we generated a CYP3A5 mutative positive quality control material and organized a national external quality assessment program.Method: A proficiency panel of 10 validated cell samples cover common CYP3A5 genetic polymorphisms was provided to 33 participating laboratories,and their genotyping results and clinical written reports were evaluated.Results: The genotypes of the 10 cell lines were validated by Sanger sequencing in our research.All of the genotyping results of the 10 cell lines were coordinated with the expected outcome.Thirty-three data sets were received,with a corresponding analytical sensitivity of 95.9%(285/297 challenges;95% confidence interval:93.0–97.9%)and an analytic specificity of 95.3%(346/363;95% confidence interval:92.6–97.2%).Thirty of the participating laboratories correctly identified the CYP3A5 allele status for all EQA samples.Three laboratories made genotyping errors and 2 of them failed to detect any of the homozygotes such as *1/*1 and *3/*3.Twenty-eight CYP3A5*3 tests reports were submitted,but many reports showed a shortage of essential information.Conclusion: The cell samples developed in our research were successfully validated by the reference laboratory and clinical laboratories,which demonstrated that the validated samples are qulified to be used as quality control materials to evaluate the quality of CYP3A5 genotyping.The proficiency testing survey highlighted the need for improved genotyping accuracy for some laboratories and standadization on the reporting of CYP3A5 genotyping results. |
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