After a positive celiac serology, what is the next diagnostic step?

After a positive celiac serology, what is the next diagnostic step?

• A. Small bowel biopsy.
• B. Immediate gluten challenge.
• C. Abdominal MRI.
• D. Colonoscopy.

Answer: (A)

Histologic confirmation with a duodenal biopsy obtained during upper endoscopy is the next step. Even after a positive serology, celiac disease is confirmed by showing characteristic mucosal damage—villous atrophy with crypt hyperplasia and increased intraepithelial lymphocytes (Marsh-type changes). This biopsy should be done while the patient is still consuming gluten, because a gluten-free diet can normalize the mucosa and yield a false-negative result. A gluten challenge isn’t needed after a positive serology, and imaging or colonoscopy won’t establish the diagnosis.

Histologic confirmation with a duodenal biopsy obtained during upper endoscopy is the next step. Even after a positive serology, celiac disease is confirmed by showing characteristic mucosal damage—villous atrophy with crypt hyperplasia and increased intraepithelial lymphocytes (Marsh-type changes). This biopsy should be done while the patient is still consuming gluten, because a gluten-free diet can normalize the mucosa and yield a false-negative result. A gluten challenge isn’t needed after a positive serology, and imaging or colonoscopy won’t establish the diagnosis.