Comparison of CYP3A5*3 genotyping assays for personalizing immunosuppressive therapy in heart transplant patients

Objective: This study aimed to compare a novel point-of-care assay that involves a flap endonuclease reaction performed using GTS-7000^® to a conventional assay that involves DNA sequencing performed using 3130xl Genetic Analyzers*. Materials and methods: This study enrolled 74 patients who underwent heart transplantation at the National Cerebral and Cardiovascular Center between May 2004 and October 2016. Each patient was genotyped as cytochrome P450 (CYP) 3A5*1/*1, CYP3A5*1/*3, or CYP3A5*3/*3. Quantitative and qualitative comparison between the two assays was carried out. Results: Four patients were genotyped as CYP3A5*1/*1, 25 as CYP3A5*1/*3, and 45 as CYP3A5*3/*3. Genotyping results of the point-of-care method were completely consistent with those of the conventional method. The total analysis time of the point-of-care method was shorter than that of the conventional method (~ 1.5 vs. 7.5 h). However, the cost of the point-of-care method was higher than that of the conventional method (~ 21 vs. 17 US$). Conclusion: Compared with a laboratory-based assay, the point-of-care assay that utilizes GTS-7000^® is accurate and rapid despite being slightly more expensive. Further trials using this assay are warranted.