Quantitative impact of pre‐analytical process on plasma uracil when testing for dihydropyrimidine dehydrogenase deficiency

• DOI: 10.1111/bcp.15536
• Publication Date: 2022-09-15T04:59:38Z
• Authors: Maud Maillard; Manon Launay; Bernard Royer; Jérôme Guitton; Elodie Gautier‐Ve...; Sophie Broutin; Camille Tron; Félicien Le Louedec; Joseph Ciccolini; Damien Richard; Hugo Alarcan; Vincent Haufroid; Naïma Tafzi; Antonin Schmitt; Marie‐Christine E...; Céline Narjoz; Fabienne Thomas
• Keywords: Dihydropyrimidine dehydrogenase; Uracil

Determining dihydropyrimidine dehydrogenase (DPD) activity by measuring patient's uracil (U) plasma concentration is mandatory before fluoropyrimidine (FP) administration in France. In this study, we aimed to refine the pre-analytical recommendations for determining U and dihydrouracil (UH2 ) concentrations, as they are essential reliable DPD-deficiency testing.U UH2 concentrations were collected from 14 hospital laboratories. Stability whole blood after centrifugation, type of anticoagulant long-term storage evaluated. The variation induced time temperature was calculated compared an acceptability range ±20%. Inter-occasion variability (IOV) assessed 573 patients double sampled testing.Storage samples centrifugation at room (RT) should not exceed 1 h, whereas cold (+4°C) maintains stability 5 hours. For correctly sampled, IOV reached 22.4% (SD = 17.9%, 0-99%). Notably, 17% them assigned with a different phenotype (normal or DPD-deficient) based on analysis their two samples. those having least one non-compliant sample, percentage increased up 33.8%. moment collection did affect DPD phenotyping result.Caution be taken when interpreting if exceeds hour RT, since it rises significantly afterwards. Not respecting conditions increases risk status misclassification.