What to expect from a blood test for coeliac disease

The test commonly checks coeliac-related antibodies and may include an immunoglobulin level that helps the laboratory interpret them. A positive result can support coeliac disease, but blood testing does not always provide the final diagnosis. A negative result is less informative if gluten has already been removed from meals or if the person has a condition affecting antibody production. Your clinician may discuss further assessment, sometimes including a specialist procedure.

Do not start a gluten-free diet before speaking with your clinician, because reducing gluten can make the antibody test harder to interpret. Follow the eating instructions given for the test and tell the clinic about previous coeliac testing, dietary changes, pregnancy, and medicines. The sample is usually taken from a vein in your arm, and normal activities can generally resume afterwards.

Arrange medical review for ongoing diarrhoea, weight loss, persistent abdominal swelling, marked tiredness, or signs of anaemia. Seek urgent help for severe dehydration, fainting, vomiting blood, black stools, or intense abdominal pain. These warning signs require assessment even before coeliac results are available.

Should I continue eating gluten before testing? Which antibodies are included? What could make the result difficult to interpret? If the result is positive or unclear, what assessment comes next?