Blood test for gluten intolerance: what it can show

Coeliac blood tests are most informative while you are still eating gluten. Stopping gluten before testing can make an antibody result harder to interpret. A positive result may lead to a specialist review and, in some cases, further testing. A negative result makes coeliac disease less likely, but your clinician may consider other explanations if symptoms continue. Gluten sensitivity without coeliac disease does not have a single blood test that confirms it. Symptoms such as bloating, loose stools, tiredness or weight change can have several causes.

Tell the clinician how long symptoms have been present, whether you have reduced gluten, and which foods trigger them. Share medicines and supplements, because some treatments can affect digestion or blood results. Do not begin a strict gluten-free diet solely on the basis of symptoms before discussing testing. Keep a brief food and symptom record, including bowel changes, abdominal discomfort and fatigue. If the test is abnormal, ask what follow-up is needed; if it is normal, ask which other causes should be checked.

Arrange medical review for ongoing diarrhoea, repeated vomiting, unexplained weight loss, persistent abdominal swelling, marked tiredness or signs of poor nutrition. Seek urgent help for severe dehydration, fainting, vomiting blood, black stools or intense abdominal pain. These warning signs need assessment regardless of whether a gluten-related blood test has been arranged.

Ask which antibodies are being checked, whether you should continue eating gluten until testing is complete, and how your symptoms will be investigated if the result is negative. You can also ask whether family history, iron deficiency or another digestive condition changes the next step.