How accurate are blood tests for celiac disease?

Blood tests for celiac disease are highly accurate. The following tests are used:

- Total serum immunoglobulin A (IgA) level: This test measures the amount of IgA in the blood. People with celiac disease often have low levels of IgA.

- Anti-tissue transglutaminase (tTG) antibodies and anti-endomysial antibodies (EMA): These antibodies are produced by the immune system in response to the consumption of gluten. The presence of these antibodies in the blood is a strong indicator of celiac disease.

Serologic testing is highly sensitive; approximately 98% of persons with celiac disease will have an abnormal result with either serologic test (tTG or EMA). The specificity is also high, approaching 95%. If clinical suspicion for celiac disease is high, additional testing should be done if serology testing comes back negative.

A confirmatory upper endoscopy with duodenal biopsies remains the gold standard for diagnosing celiac disease, even in the presence of positive serology in symptomatic patients.