Virtually everyone prefers a simple cheek swab to an invasive blood test but that’s not the reason celiac disease risk screening should always start with genetics. The reason is screening tests are not for diagnosing disease. The primary purpose of screening tests is to detect risk factors for disease in healthy individuals.
Celiac disease screening antibody tests are INEFFECTIVE in healthy individuals:
- Lacking inherited celiac risk genetics DQ2 and DQ8: These individuals cannot make celiac disease-specific antibodies to gluten and have less than 1% chance of developing celiac disease. An estimated 60-70% of the population is negative for DQ2 and DQ8 genetics. They will not benefit from celiac disease antibody testing.
- On a gluten-free diet: These individuals may or may not have inherited celiac risk genes DQ2 and/or DQ8 but antibody testing will produce false-negative results if they are not consuming gluten in their diet.
Yet, many laboratories and direct to consumer websites are promoting celiac disease screening using blood-based testing without informing the test users of these two important facts:
- Individuals lacking DQ2 and/or DQ8 genetics cannot make the tested celiac-specific antibodies.
- Anyone who has already adopted a gluten-free diet (regardless of celiac risk genetics) will have negative results.
Celiac antibody tests are ESSENTIAL in individuals:
- Who has positive genetics and are consuming gluten.
- Who are experiencing celiac disease signs and symptoms who need confirmation of a clinical diagnosis.
Screening tests are designed to prevent the development of disease in healthy individuals. Yet antibody testing for healthy individuals on a gluten-free diet (or those with negative genetics) is not beneficial due to the high false-negative rate. For screening healthy individuals, genetic testing should come first. Genetic positive and/or symptomatic individuals who are consuming dietary gluten can then be regularly monitored by antibody testing.
In conclusion: Celiac genetic health risk testing identifies individuals who would benefit from regular antibody testing and those who can forgo further celiac disease screening.