This kit is used for genotyping human CYP2C19 gene * 1 (wild type), * 2 (c.681G>A) and * 3 (c.636G>A) from genomic DNA extracted from patients' peripheral blood. The hepatic CYP2C19 enzyme contributes to the metabolism of a large number of clinically relevant drugs such as antidepressants, benzodiazepines, mephenytoin, some proton pump inhibitors, and clopidogrel. The test results of can provide guidance for personalized clinical treatment.