A Simple and Rapid UPLC-UV Method for Detecting DPD Deficiency in Patients With Cancer

Detecting patients with dihydropyrimidine dehydrogenase (DPD) deficiency has become a significant concern in clinical oncology. Measuring physiologic plasma uracil levels and/or the plasma uracil-to-dihydrouracil metabolic ratio is a widely used surrogate approach for assessing DPD phenotype without directly measuring enzymatic activity. Given the growing demand for patient analysis, there is an urgent need to develop simple, rapid, and cost-effective methods suitable for routine screening.

To address this need, we have developed and validated a robust ultraperformance liquid chromatography-ultraviolet (UPLC-UV) method with a shortened analytical runtime of 12 minutes, designed to meet the requirements of large-scale, upfront screening. This method reliably quantifies uracil (U) over a range of 5–500 ng/mL (measured at 265 nm) and dihydrouracil (UH2) over a range of 40–500 ng/mL (measured at 210 nm) in plasma, with no chromatographic interference. In routine DPD deficiency screening, the method ML 210 effectively differentiates nondeficient patients (U levels <16 ng/mL) from patients at risk of severe toxicity (U levels >16 ng/mL).

Results from one month of routine testing demonstrated that, while no complete DPD deficiencies were detected, 10.7% of patients screened exhibited partial DPD deficiency and would require dose adjustments. This method, which employs a straightforward preanalytical solid-phase extraction procedure and utilizes standard UPLC equipment, is both cost- and time-efficient, making it easily implementable in laboratories seeking to establish routine DPD testing.