In a patient with iron-deficiency anemia and significantly elevated tissue transglutaminase antibodies, which result would most strongly support a coeliac disease diagnosis?

• A. Low ferritin
• B. Normal tTG
• C. Elevated CRP
• D. Elevated tissue transglutaminase antibodies

Answer: (D)

Elevated tissue transglutaminase antibodies are the strongest clue for coeliac disease because anti-tTG IgA is the most reliable serologic marker for gluten-related autoimmune damage in the small intestine. In coeliac disease, gluten triggers an immune response against tissue transglutaminase, leading to villous atrophy and malabsorption, which explains iron-deficiency anemia. A significantly raised tTG level directly supports this diagnosis. Low ferritin shows iron stores are depleted but isn’t specific for coeliac, while an elevated CRP is a nonspecific marker of inflammation and doesn’t point to coeliac. A normal tTG would argue against the diagnosis, and while biopsy can confirm the condition, the strongest single indicator among the options is the elevated tTG antibodies.