Indeed, both the FDA and CPIC highlight the contraindication of this medication to carriers of the HLA-B*5701 allele due to the high risk of hypersensitivity reactions (HSR) (Centers for Medicare & Medicaid Services, 2018; BlueCross Blueshield of Western New York, 2018; Quest Diagnostics, 2015; PGX Tests Determined to be Medicially Necessary for Medicare Coverage.; Local Coverage Determination (LCD)), while economic evaluation results with an ICUR of $36,700/QALY (lower than the $50,000/QALY threshold) justify its cost-effectiveness (60). Here, HLA-B is linked to hypersensitivity.