Patients with one or two copies of the HLA-A*31:01:02 allele who are treated with carbamazepine may have an increased risk of severe cutaneous adverse reactions as compared to patients with no HLA-A*31:01:02 alleles or negative for the HLA-A*31:01:02 test. However, conflicting evidence has been reported. Other genetic and clinical factors may also influence a patient's risk of adverse reactions.