If serology is positive in celiac evaluation, what is the next step to confirm the diagnosis?

• A. Endoscopy with duodenal biopsy
• B. Abdominal ultrasound
• C. Colonoscopy
• D. MRI abdomen

Answer: (A)

Confirming celiac disease requires histologic evidence of small intestinal damage. After a positive serology, the next step is endoscopy with duodenal biopsy to directly examine the mucosa. The biopsy can reveal the characteristic changes of celiac disease: villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes. Obtaining multiple biopsies from different parts of the duodenum (including the bulb and distal duodenum) accounts for patchy involvement and increases diagnostic accuracy.

Other imaging tests like abdominal ultrasound, colonoscopy, or MRI abdomen do not assess the small-bowel mucosal architecture required for diagnosis. They may be useful for evaluating other problems or complications but cannot confirm celiac disease on their own.