Patients with coeliac disease almost always have specific variants of the human leukocyte antigens, HLA-DQ2 and HLA-DQ8. These variants are necessary, but not sufficient, for the disease to occur. Up to 30% of some Caucasian populations have these specific variants, but only 5-10% of such people ever develop coeliac disease.
The presence of these variants indicates that a person is at increased risk of developing coeliac disease. Nonetheless, the majority of people with these variants will not develop coeliac disease.
The absence of these variants effectively excludes a diagnosis of coeliac disease in the patient now or in the future. This is the principle value of the test i.e. excluding the current or potential diagnosis of coeliac disease in a symptomatic patient, a patient on a gluten-free diet, or in the relatives of a person with coeliac disease.
This is an assay for heritable variants which can alter the probability that a person will develop a disorder. The test result is not, in isolation, diagnostic of a disease and the test result is not necessarily clinically significant for the patient's relatives.
Real time PCR for direct qualitative detection of HLA-DQ2, DQ8, DQA1*02, DQA1*05 and DR4 genes associated with coeliac disease.
Requesting the test
This test can be requested by any medical practitioner.
4 mL blood in EDTA. Specimens may be collected by the requesting practitioner or at any Sonic Healthcare collection centre (see link below).
To help ensure the quality of the test, a genetic test should be done with a dedicated sample whenever possible i.e. a sample collected specifically for that test rather than a sample that is used for multiple tests.
We recommend that the patient or another adult check the labelling of request forms and sample tubes.