Celiac Genetic Test (HLA-DQ2 and DQ8)

Also written as: HLA-DQ2/DQ8 typing, Celiac HLA test

A gene test showing whether celiac disease is genetically possible - not whether it is present.

What it measures

Whether the genes HLA-DQ2 and HLA-DQ8 are present. These genes encode immune system proteins that celiac disease requires in order to develop - essentially all people with celiac carry one of them.

Why a doctor orders it

It is used to help rule celiac out: when antibody test results are ambiguous, when a gluten-free diet was started before testing and antibody tests can no longer be trusted, or in close relatives of someone with celiac. Unlike the antibody tests, it works regardless of what the person is eating.

What is generally associated with a higher result

A positive result generally means only that celiac disease is genetically possible. Roughly a third of the general population carries DQ2 or DQ8, and the large majority of carriers never develop celiac disease. On its own, a positive result diagnoses nothing.

What is generally associated with a lower result

A negative result generally makes celiac disease very unlikely, now and in the future, because the condition almost never develops without these genes. That ruling-out power is the main reason the test exists.

Everyday things that move this number

Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:

Nothing day to day - the result reflects inherited genes and does not change with diet, symptoms, or time
Not affected by whether gluten is currently being eaten, unlike the celiac antibody tests
Lab-to-lab differences in exactly which gene variants are tested and how they are reported

Questions to take to your appointment

Given this result, is any further celiac testing worthwhile?
If antibody testing comes next, do I need to be eating gluten beforehand?
Is this result relevant for my close relatives?

Build a printable questionnaire with your own results →

Where to read more

MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .

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