Improvements in CYP2C9 Genotyping Accuracy Are Needed: A Report of the First Proficiency Testing for Warfarin-related CYP2C9 and VKORC1 Genotyping in China. Issue 2 (August 2015)

• Record Type: Journal Article
• Authors: Lin, Guigao; Yi, Lang; Zhang, Kuo; Sun, Yu; Wang, Lunan; Zhang, Rui; Xie, Jiehong; Li, Jinming
• Is Part Of: Journal of cardiovascular pharmacology. Volume 66:Issue 2(2015)
• Publication Date: 2015-08
• Subjects: CYP2C9 -- genotyping -- proficiency testing -- VKORC1 -- warfarin; Cardiovascular Diseases -- drug therapy -- Periodicals; Cardiovascular System -- drug effects -- Periodicals; Cardiovascular pharmacology -- Periodicals; Cardiovascular agents -- Periodicals; Cardiovascular agents; Cardiovascular pharmacology; Periodicals; 615.7105
• DOI: 10.1097/FJC.0000000000000254
• Languages: English
• ISSNs: 0160-2446

Abstract

Abstract : Abstract: Warfarin is the most commonly used oral anticoagulant in clinical practice. The cytochrome P450 2C9 ( CYP2C9 ) and vitamin K epoxide reductase complex 1 ( VKORC1 ) genotypes have been confirmed to be associated with warfarin dose requirements. Accurate genotyping results are of particular importance for obtaining reliable genotype-guided warfarin dosing information. This study aims to determine analytic performance of laboratories offering CYP2C9 and VKORC1 testing in China. A proficiency panel of 15 validated cell samples covering common CYP2C9 and VKORC1 genetic polymorphisms was provided to 31 participating laboratories, and their genotyping results were evaluated. Fourteen data sets (45.2%) performed well with the entire panel of samples, and 17 data sets (54.8%) reported at least one genotyping error. For VKORC1 ( −1639G>A ), participating laboratories were 100% successful in detecting genotypes of GG, GA, and AA . For CYP2C9, participants were greater than 90% successful in detecting genotypes of *1/*1, *1/*2, *1/*3, *2/*3, and *3 / *3 . However, 15 laboratories failed to detect rarely encountered variant genotype *2 / *2 . The poor performance of CYP2C9 genotyping may be because of the limitation of methodologies used for detecting CYP2C9*2 allele. The proficiency testing survey highlighted the need for improving genotyping accuracy for some laboratories in this field.