PGx 5-fluorouracil

The result is reported as the DPYD diplotype with the derived DPD metaboliser phenotype. Genotype-to-phenotype translation follows the consensus activity-score framework maintained by and , spanning normal, intermediate and poor metaboliser status. This assignment, and the guidance derived from it, are revised over time and held in the maintained pharmacogenomic databases linked below rather than fixed on this page.

A negative result reflects only the four alleles tested and does not exclude DPD deficiency from rare or novel DPYD variants, structural variation or non-genetic causes. The four consensus variants are found predominantly in individuals of European ancestry and are largely absent in East Asian ancestry, so a normal result is correspondingly less informative outside those groups; c.557A>G is the variant of principal relevance in individuals of African ancestry and is not covered here. Where HapB3 is determined from the tag variant c.1236G>A rather than from c.1129-5923C>G itself, linkage between the two is not complete, so the haplotype can be misassigned. Where DPD status is assessed by uracil-based phenotyping instead of, or alongside, genotyping, moderate or severe renal impairment raises plasma uracil independently of DPD activity, so a deficiency can be diagnosed that is not present and the fluoropyrimidine underdosed as a result. Allele functional classifications are subject to ongoing revision; the linked databases hold the current version.

Content reviewed against the current guidelines on 27 July 2026. Pharmacogenomic classifications are periodically revised; the linked databases above hold the day-current version.

European regulators recommend testing for DPD deficiency before starting fluoropyrimidine therapy, and in Germany the issued a corresponding Rote-Hand-Brief implementing this position.

For current, actionable guidance consult the maintained external resources: first the current prescribing information for the drug; the CPIC guideline for fluoropyrimidines and DPYD, held with the other pharmacogenomic annotations at . and .

Results are interpreted in the individual clinical context, and the treatment decision rests with the treating physician.

Content reviewed against the current guidelines on 27 July 2026. Pharmacogenomic classifications are periodically revised; the linked databases above hold the day-current version.

• Amstutz U, Henricks LM, Offer SM, Barbarino J, Schellens JHM, Swen JJ, et al. Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for dihydropyrimidine dehydrogenase genotype and fluoropyrimidine dosing: 2017 update. Clin Pharmacol Ther. 2018;103(2):210-216. PMID: .
• Pratt VM, Cavallari LH, Fulmer ML, Gaedigk A, Hachad H, Ji Y, et al. DPYD genotyping recommendations: a joint consensus recommendation of the Association for Molecular Pathology, American College of Medical Genetics and Genomics, Clinical Pharmacogenetics Implementation Consortium, College of American Pathologists, Dutch Pharmacogenetics Working Group of the Royal Dutch Pharmacists Association, European Society for Pharmacogenomics and Personalized Therapy, Pharmacogenomics Knowledgebase, and Pharmacogene Variation Consortium. J Mol Diagn. 2024;26(10):851-863. PMID: .
• Lunenburg CATC, van der Wouden CH, Nijenhuis M, Crommentuijn-van Rhenen MH, de Boer-Veger NJ, Buunk AM, et al. Dutch Pharmacogenetics Working Group (DPWG) guideline for the gene-drug interaction of DPYD and fluoropyrimidines. Eur J Hum Genet. 2020;28(4):508-517. PMID: .
• Turner AJ, Haidar CE, Yang W, et al. Updated DPYD HapB3 haplotype structure and implications for pharmacogenomic testing. Clin Transl Sci. 2024;17(1). PMID: .
• Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM). Rote-Hand-Brief zu 5-Fluorouracil (i.v.): Risiko der Fehlinterpretation des Uracilspiegels zur Bestimmung eines Dihydropyrimidin-Dehydrogenase (DPD)-Mangels bei mittelschwerer oder schwerer Nierenfunktionsstörung. Bonn: BfArM; October 24, 2024. Available from:
• European Medicines Agency. EMA recommendations on DPD testing prior to treatment with fluorouracil, capecitabine, tegafur and flucytosine. Amsterdam: European Medicines Agency; April 30, 2020. Available from:
• Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM). Rote-Hand-Brief zu 5-Fluorouracil- (i.v.), Capecitabin- und Tegafur-haltigen Arzneimitteln: Tests vor Behandlungsbeginn zur Identifizierung von Patienten mit DPD-Mangel. Bonn: BfArM; June 4, 2020. Available from:
• European Medicines Agency. Xeloda (capecitabine): EPAR, product information, section 4.3 Contraindications. Product information last updated May 2, 2025. Available from:
• US Food and Drug Administration. XELODA (capecitabine) tablets, prescribing information. Boxed warning and Warnings and Precautions 5.1: serious adverse reactions or death in patients with complete DPD deficiency. Label revised October 2025. Available from:
• Deutsche Gesellschaft für Hämatologie und Medizinische Onkologie (DGHO), in cooperation with Deutsche Gesellschaft für Humangenetik, Arbeitsgemeinschaft Internistische Onkologie, and Schweizerische Gesellschaft für Medizinische Onkologie. Positionspapier: Dihydropyrimidin-Dehydrogenase (DPD)-Testung vor Einsatz von 5-Fluorouracil, Capecitabin und Tegafur. Berlin: DGHO; June 2020. Available from: