DPD 5-Fluorouracil Toxicity

CPT: 81232
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  • 5FU
  • Dihydropyrimidine Dehydrogenase

Expected Turnaround Time

6 - 10 days

Specimen Requirements


Whole blood or LabCorp buccal swab kit (buccal swab collection kit contains instructions for use of a buccal swab)


7 mL whole blood or LabCorp buccal swab kit

Minimum Volume

3 mL whole blood or two buccal swabs


Lavender-top (EDTA) tube, yellow-top (ACD) tube, or LabCorp buccal swab kit

Storage Instructions

Maintain specimen at room temperature or refrigerate at 4°C.

Causes for Rejection

Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; one buccal swab; wet buccal swab

Test Details


Variability in response (efficacy and toxicity) to 5-fluorouracil (5-FU) chemotherapy has been linked to the rate-limiting enzyme in the drug's catabolic pathway, known as dihydropyrimidine dehydrogenase (DPD).


This procedure will only detect the presence of the wild type or mutant allele for the DPD IVS14+1G>A mutation.

This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.


Polymerase chain reaction (PCR); restriction enzyme digestion; gel electrophoresis

Additional Information

DPD deficiency results in excessive amounts of 5-FU available to be anabolized to its active metabolite and is relatively undetectable by clinical observation prior to 5-FU administration. Extensive studies have associated both profound and partial deficiency in DPD activity with severe unanticipated toxicity after 5-FU administration. Numerous studies genotyping DPD deficient patients, their family members, and healthy individuals have shown that the splice-site mutation (IVS14+1G>A) is the most characterized and frequently observed allele associated with decreased DPD enzyme activity. Screening for the presence of this mutation in the Caucasian population showed frequencies of 0.91% homozygous and 1.8% heterozygous for the IVS14+1G>A allele.


Lee A, Ezzeldin H, Fourie J, Diasio R. Dihydropyrimidine dehydrogenase deficiency: impact of pharmacogenetics on 5-fluorouracil therapy. Clin Adv Hematol Oncol. 2004 Aug; 2(8):527-532. 16163233
van Kuilenburg AB, Muller EW, Haasjes J, et al. Lethal outcome of a patient with a complete dihydropyrimidine dehydrogenase (DPD) deficiency after administration of 5-fluorouracil: frequency of the common IVS14+1G>A mutation causing DPD deficiency. Clinical Cancer Research. 2001 May; 7(5):1149-1153.11350878


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
511176 DPD 5-Fluorouracil Toxicity 45284-7 511186 Result: 45284-7
511176 DPD 5-Fluorouracil Toxicity 45284-7 511235 Mutation: N/A
511176 DPD 5-Fluorouracil Toxicity 45284-7 511189 Director Review: 72486-4

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