Patients with one or two copies of the HLA-B*15:11:01 allele may have an increased risk of Severe Cutaneous Adverse Reactions, such as Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis, when treated with carbamazepine as compared to patients with no HLA-B*15:11:01 alleles or negative for the HLA-B*15:11:01 test. However, conflicting evidence has been reported. Other genetic and clinical factors may also influence risk of carbamazepine-induced adverse reactions.