Generally, antibody blood tests and biopsies are sensitive and specific enough to clearly diagnosis celiac disease. However, because no test is perfect, a firm diagnosis should include antibody blood screening, biopsies and response to a gluten-free diet.
Although biopsies are the standard for diagnosis, periodically they do not lead to a clear diagnosis. Many factors can contribute to an unclear biopsy, such as:
- Incorrect orientation of the biopsies when taken from the small intestine.
- Insufficient number of biopsies from a broad sample of the small intestine.
- Inexperience of the pathologist.
- Gluten-free diet started prior to biopsies.