DPD 5-Fluorouracil Toxicity

Test ID: 


CPT code:



Dihydropyrimidine Dehydrogenase

Clinical Use:

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).

Test 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.

Specimen Type:

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

Requested Volume: 


Minimum Volume: 


Container Type: 

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

Storage Instructions:

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

Rejection Criteria:

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


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MCI Diagnostic

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Tulsa, Oklahoma 74136

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Sun: 7AM-3PM

Government Contract

Mon – Sat: 7AM-11PM

Sun: 7AM-3PM


Mon – Sat: 7AM-11PM

Sun: 7AM-3PM

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