HESI Inflammatory Bowel Disease Case Study Practice Test

Testing TPMT activity helps tailor azathioprine or 6-mercaptopurine dosing to minimize the risk of myelosuppression. TPMT is the enzyme that metabolizes thiopurines, and people with low or absent TPMT activity can accumulate harmful levels of active metabolites, leading to bone marrow suppression. Knowing TPMT status before starting therapy allows dose adjustments or considering alternative treatments so you can use thiopurines safely and effectively. If a patient has normal TPMT activity, standard dosing with routine monitoring is appropriate. If TPMT activity is reduced, clinicians typically reduce the thiopurine dose (often substantially) and monitor blood counts closely to prevent cytopenias. TPMT testing does not measure disease activity, detect latent TB, or predict steroid response, so those aspects are evaluated by separate tests and clinical assessments.