AUDT does not recommend any specific test, however, we recommend using a CLIA-approved test that includes several of the most common alleles including DPYD*2A, DPYD*13, DPYD p.D949V, and DPYD HapB3. A list of these tests can be found at the NCBI Genetic Testing Registry.
How long does it take to get the results?fishnyc222022-11-01T18:13:41-04:00
This depends on several factors including the test ordered and insurance coverage. In general, testing costs $150-$500. Some insurance covers testing, in which case the patient may not have any payment. It may not be possible to determine whether there will be any cost to the patient prior to ordering.
Is there evidence that reducing fluoropyrimidine dosing in DPYD carriers reduces treatment effectiveness?fishnyc222022-11-01T18:13:03-04:00
No, there is no evidence of reduced efficacy. There is some evidence that efficacy is the same but this has not been confirmed. It is confirmed that reducing doses results in similar drug concentrations and toxicity risk, so it is reasonable to assume that efficacy is also similar.
The risk of toxicity depends on many factors, but generally is >50%, with ~30% risk of hospitalization and ~3% risk of death. Of note, DPYD carriers are not guaranteed to experience toxicity and non-carriers are not guaranteed to avoid toxicity.