This result signifies that the patient has two copies of a no function allele. Based on the genotype result this patient is predicted to be a TPMT poor metabolizer. This patient may be at a high risk for an adverse reactions to medications that are metabolized by TPMT (eg. thiopurines). To avoid an untoward drug response, dose adjustments or or alternative therapy may be necessary for medications metabolized by TPMT. However, thiopurines can be affected by a patient's TPMT and NUDT15 phenotype. Please consult a clinical pharmacist for more information about how TPMT and NUDT16 metabolic status influences drug selection and dosing.