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- Dihydropyrimidine Dehydrogenase
Expected Turnaround Time
6 - 10 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
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
3 mL whole blood or two buccal swabs
Lavender-top (EDTA) tube, yellow-top (ACD) tube, or LabCorp buccal swab kit
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
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.
Polymerase chain reaction (PCR); restriction enzyme digestion; gel electrophoresis
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.
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|511176||DPD 5-Fluorouracil Toxicity||511186||Result:||45284-7|
|511176||DPD 5-Fluorouracil Toxicity||511235||Mutation:||N/A|
|511176||DPD 5-Fluorouracil Toxicity||511189||Director Review:||72486-4|