Pretherapeutic screening for Dihydropyrimidine deshydrogenase deficiency in measuring uracilemia in dialysis patients leads to a high rate of falsely positive results.

Phenotyping based on measuring plasma [U] before a dialysis sessions in ESRD patients is associated with an unacceptable high rate of false positives. The optimal strategy for the identification of patients with DPD deficiency in this population would be the monitor the [UH2]:[U] ratio, which remains unaffected.