American Board of Internal Medicine (ABIM) Certification Practice Exam

Which serologic markers are sensitive and specific for celiac disease?

1. Anti-nuclear antibodies and anti-SM antibodies

2. IgA tissue transglutaminase (tTG) antibodies and endomysial antibodies (EMA)

3. Anti-dsDNA and anti-SSA antibodies

4. Serum electrolytes and creatinine levels

The correct answer is: IgA tissue transglutaminase (tTG) antibodies and endomysial antibodies (EMA)

IgA tissue transglutaminase (tTG) antibodies and endomysial antibodies (EMA) are the serologic markers that are both sensitive and specific for celiac disease. Tissue transglutaminase is an enzyme that modifies gluten proteins, and in individuals with celiac disease, the immune system produces antibodies against this enzyme, indicating an autoimmune response. The tTG antibodies are considered the first-line screening test for celiac disease due to their high sensitivity. When screening is performed, a positive test for IgA tTG generally leads to further evaluation for confirmatory tests, such as EMA testing. Endomysial antibodies are typically present in individuals with celiac disease as well, and while they are more specific than tTG antibodies, they are less sensitive. Nevertheless, the presence of both antibodies in a patient strongly indicates celiac disease. The combination of these two tests effectively captures a high percentage of diagnosed cases of celiac disease due to their reliability. The other options mentioned do not relate directly to celiac disease. Anti-nuclear antibodies and anti-Smith antibodies are markers associated with systemic lupus erythematosus and other autoimmune disorders, while anti-dsDNA and anti-SSA antibodies pertain to lupus and