Which test is most specific and sensitive for the diagnosis of celiac disease?

Which test is most specific and sensitive for the diagnosis of celiac disease?

• A. Anti-transglutaminase 2 (TG2) antibody
• B. Anti-acetylcholine receptor antibody
• C. Anti-Smith antibody
• D. Isolation of T cells reactive to pancreatic antigens

Answer: (A)

Testing for celiac disease relies on a serologic marker that combines high sensitivity with high specificity: IgA antibodies to tissue transglutaminase (TG2). These antibodies arise in most individuals with active celiac disease because TG2 is a major autoantigen in the condition, so a positive TG2 IgA test strongly supports the diagnosis. Because some people have selective IgA deficiency, it’s important to check total IgA levels; if IgA is deficient, TG2 IgG or other IgG-based tests are used to avoid false negatives. While anti-endomysial antibodies are also highly specific, they require more subjective, labor-intensive testing and are less practical for routine screening. The other antibodies listed target diseases unrelated to celiac disease—for example, anti-acetylcholine receptor antibodies are seen in myasthenia gravis and anti-Smith antibodies in SLE—so they don’t diagnose celiac disease. A positive TG2 IgA test is usually followed by clinical correlation and may be confirmed with a small bowel biopsy showing characteristic villous atrophy if needed.

Testing for celiac disease relies on a serologic marker that combines high sensitivity with high specificity: IgA antibodies to tissue transglutaminase (TG2). These antibodies arise in most individuals with active celiac disease because TG2 is a major autoantigen in the condition, so a positive TG2 IgA test strongly supports the diagnosis. Because some people have selective IgA deficiency, it’s important to check total IgA levels; if IgA is deficient, TG2 IgG or other IgG-based tests are used to avoid false negatives. While anti-endomysial antibodies are also highly specific, they require more subjective, labor-intensive testing and are less practical for routine screening. The other antibodies listed target diseases unrelated to celiac disease—for example, anti-acetylcholine receptor antibodies are seen in myasthenia gravis and anti-Smith antibodies in SLE—so they don’t diagnose celiac disease. A positive TG2 IgA test is usually followed by clinical correlation and may be confirmed with a small bowel biopsy showing characteristic villous atrophy if needed.