Testing Options & Diagnosis
The diagnosis of celiac disease may be intially missed because symptoms can be similar to those of other diseases including diseases of the gastrointestinal system. However, there are several currently available blood tests that are used to screen for celiac disease. These tests are very sensitive and specific for celiac disease and are cost effective. The tests detect autoantibodies that are present in higher than normal levels in the blood of patients who have celiac disease. Autoantibodies are proteins produced by the immune system that, instead of reacting against foreign substances, react against components of the body itself.
The first tests physicians usually perform to screen for the diagnosis celiac disease are blood tests for:
- Anti-tissue transglutaminase antibodies(tTGA) with or without IgA levels
- IgA anti-endomysial antibodies (EMA)
It is very important that a patient eats a diet containing gluten prior to having blood tests for celiac disease-related autoantibodies; otherwise the tests may fail to detect celiac disease.
If screening blood tests suggest a patient has celiac disease, the physician will usually perform a small bowel biopsy to confirm the diagnosis. In this test, very small tissue samples are taken from the small intestine using a long, thin tube passed through the mouth and stomach and into the small intestine (an endoscope). From these tissue samples, the physician can confirm the diagnosis celiac disease and, if the disease is present, determine how much damage the lining of the intestine has sustained.