After a celiac test has shown positive results you may still have doubts whether it’s celiac disease or can a positive celiac blood test mean something else? Let’s explore this issue in more detail.
People with celiac disease who eat gluten have higher than normal levels of certain antibodies in their blood. These antibodies are produced by the immune system as it perceives gluten (proteins found in wheat, rye, and barley) as a threat. You must be on a gluten-free diet for antibody (blood) testing to be accurate.
The tTG-IgA test will be positive in about 98% of celiac patients who are on a diet containing gluten. This is called the sensitivity of the test.
There is still a small risk of a false-positive test result. There we are again with our question: can a positive celiac blood test mean something else? The answer is yes, especially for people with associated autoimmune disorders such as type 1 diabetes, autoimmune liver disease, Hashimoto’s thyroiditis, psoriatic or rheumatoid arthritis, and heart failure who do not have celiac disease.
There are other antibody tests available to double-check for potential false positives or false negatives, but due to the potential false antibody test results, a biopsy of the small intestine is the only most accurate way to diagnose celiac disease.
At the same time, given the high predictive value of a positive serological test result (> 95%), increased TGA-IgA 10 norms the upper limit of the reference value and a positive test for EMA-IgA in a separate blood sample reduce the risk of false-positive results. How consequently, the diagnosis of celiac disease can be made without a biopsy of the small intestine.
The endomysial IgA antibody (EMA) test is generally for people who have difficulty diagnosing celiac disease. It is not as sensitive as the tTG-IgA test and is more expensive.