There are two types of home celiac tests: antibody testing and genetic testing.
Antibody tests use a blood sample to check for antibodies that have a known association with celiac disease. An antibody is a protein produced by the immune system in the presence of celiac disease. Celiac antibody tests evaluate the presence of specific antibodies that are found at high levels only in people who have celiac disease.
Genetic celiac tests evaluate the presence of a genetic marker associated with the presence of celiac disease. However, even when a person has this genetic marker, they may not develop the symptoms of celiac disease—this is not a diagnostic test. A genetic test will instead give you a better idea of how likely you are to develop celiac. The definitive diagnostic test is an EGD (endoscope) and biopsy. Before completing this test, you will be asked to eat a specific amount of gluten, for the most accurate results.
A person’s primary care physician may request they use a home celiac test to guide subsequent testing and determine the origin of a person’s symptoms. Typically, the first test is an antibody blood test, after which a physician may follow up with an upper endoscopy. If the antibiotic tests are negative, but symptoms persist, genetic testing may be used to rule out celiac disease.