Which laboratory test is most accurate for diagnosing celiac disease?

The most accurate laboratory test for diagnosing celiac disease is the test for anti-tissue transglutaminase antibodies. This test measures the presence of antibodies that are produced in response to the enzyme tissue transglutaminase, which is important in the breakdown of gluten. In individuals with celiac disease, an autoimmune reaction occurs when gluten is ingested, leading to the production of these antibodies.

The testing for anti-tissue transglutaminase antibodies is considered highly sensitive and specific for celiac disease, making it a reliable first-line screening tool. A positive result generally indicates the presence of celiac disease, especially when accompanied by supportive symptoms and the appropriate dietary history.

While testing for anti-gliadin antibodies was once used in the diagnosis of celiac disease, it is now deemed less reliable and has been largely replaced by the tissue transglutaminase antibody test, which provides a more accurate assessment.

A rectal biopsy, although it can be used to confirm celiac disease, is an invasive procedure and not the initial diagnostic method. It typically comes into play after serological tests suggest celiac disease, to assess intestinal damage and confirm the diagnosis.

A complete blood count is not specific for diagnosing celiac disease. While it can