DPYD (DPD) Genotyping
The DPYD gene encodes an enzyme known as dihydropyrimidine dehydrogenase (DPYD). This enzyme is critical to the metabolism of fluoropyrimidine drugs such as fluorouracil/5-FU (Adrucil®) and capecitabine (Xeloda®) . These drugs are all part of chemotherapy treatments for many cancers including head and neck, gastrointestinal and colorectal cancers. The DPYD gene is also the rate-limiting step in the breakdown of pyrimidines, such as uracil and thymine. Mutations, or variations, in DPYD are known to cause severe 5-FU toxicity as a result of decreased DPYD activity.
Indications for DPYD Testing
Patients who are candidates for fluorouracil or capecitabine therapy should receive DPYD genotyping prior to starting their treatment regimen, especially if the patients have a personal or family history of 5-FU toxicity. All three DPYD metabolizer phenotypes carry a clinically actionable recommendation for treatment and dosing.
Check with your insurance provider to see if DPYD genotyping is covered. The CPT code for DPYD testing is 81232 (provided as guidance only).
Click here to order testing supplies or call Client Services at 800-837-8362.
- Buccal Swabs: 4 sterile buccal swabs
- Blood: 5-10cc whole blood lavender-top EDTA or yellow-top ACD-A tubes
- Turnaround Time: 10 business days, faster turnaround available for clinical trials
REFERENCES: 1. Amstutz, U., Henricks, L. M., Offer, S. M., Barbarino, J., Schellens, J. H., Swen, J. J., . . . Schwab, M. (2017). Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for Dihydropyrimidine Dehydrogenase Genotype and Fluoropyrimidine Dosing: 2017 Update. Clinical Pharmacology & Therapeutics,103(2), 210-216. doi:10.1002/cpt.911