Diagnosising Celiac Disease
Recommended tests for CD include both serological screening (blood tests) and multiple biopsies of the small intestine through endoscopy. If the serological screening is negative and there are no reasons to suspect that a patient has CD, it is generally not considered necessary to perform an endoscopy.
The most reliable blood test is the tissue transglutaminase (tTG) test. A total IgA serum test should also be performed to ensure that the test is not falsely negative. People whose bodies do not produce IgA will have a negative tTG score.
While a genetic test is not required for diagnosis, it can be used to rule out CD: if you don't have the genes, you don't have it.