DPYD Genotyping

Test codes M1.7, M3.7, M6.5, M14.5, M15.7, M16.4, M17.4, M219.3, M220.3, M222.4, M226.3, M227.3, M236.2, M237.2, M238.2

Visit the National Genomic Test Directory.

DPYD Genotyping prior to fluoropyrimidine chemotherapy (Test codes M1.7, M3.7, M6.5, M14.5, M15.7, M16.4, M17.4, M219.3, M220.3, M222.4, M226.3, M227.3, M236.2, M237.2, M238.2)

Around 3-9% of the population carry a DPYD genetic variant causing DPD deficiency, resulting in a substantial risk of serious and potentially fatal adverse effects with fluoropyrimidine chemotherapy treatment. The Medicines and Healthcare products Regulatory Agency (MHRA) advise that all patients are tested for DPD deficiency prior to commencing treatment. Currently commissioned tests consider the most common DPYD variants only. Despite a ‘normal’ test result, patients may still experience toxicity due to rare genetic variants that have not been detected, or other clinical factors.

Patients planned to receive fluoropyrimidine chemotherapy (capecitabine, 5-fluorouracil), who have not previously been genotyped for DPYD.

Eligibility criteria for genomic tests can be found in the National Genomic Test Directory.

This lists the clinical specialties that would be expected to request for a given clinical indication and sets out which patients should be considered for testing.

The GMS test order form is available below:

GMS Test Order Form v2.3

This should be completed in full & include the test indication ‘DPYD genotyping prior to fluoropyrimidine treatment’.

Alternatively, local test request forms with the equivalent information are acceptable.

Please ensure that the patient identity has been verified before taking the sample. • The sample should be labelled with at least 3 patient identifiers including the patient’s name & date of birth. • Please send the completed referral form and the labelled patient sample (2-4ml of EDTA blood) to the designated Genomics Laboratory Hub:

South West Genomics Laboratory Hub Bristol Genetics Laboratory Southmead Hospital Westbury-on-Trym Bristol BS10 5NB

Transportation instructions

· Samples should be sent at room temperature. If there is a delay in sending the sample can be refrigerated at +4 degree Celsius for a few days without affecting quality.

· The sample container should be leak-proof and must be placed in a transparent sample bag with the paperwork attached but not in the same compartment as the container. The outer sample packaging must comply with PI 650 for category B substances. The package should be clearly labelled ‘diagnostic specimen UN3373’.

· Samples should be sent to the laboratory via your local hospital transport services or directly using first class via the Royal Mail postal services.

For a full list of sample requirements and transport guidance, please visit the samples and transport page of the website. 

LAMP coupled melt-curve analysis is used to genotype the common DPYD variants DPYD c.1905+1G>A, c.1679T>G, c.2846A>T, c.1129-5923C>G. From Autumn 2025, a further variant c.557A>G will be added to standard testing.

Reports will be returned by email within 5 days as a pdf-document. • Report recipient details (name, job title and email address) should be specified on the referral form. • Alternatively, the GLH will manage a list of recipients for your region; contact SWGLHcancer@nbt.nhs.uk at the SWGLH to discuss what information is required to set this up.