The CYP2C9*2 allele is assigned as a decreased function allele by CPIC. Patients with CYP2C9*2 in combination with a normal, decreased, or no function allele may have increased risk of bleeding when treated with acenocoumarol as compared to patients with two normal function alleles. However, conflicting evidence has been reported. This drug-variant pair has been assigned a 鈥渘o recommendation鈥?by DPWG, as it was determined to be not clinically actionable.Other genetic and clinical factors may also influence the risk of bleeding when treated with acenocoumarol.