Which test is diagnostic for ulcerative colitis?

Which test is diagnostic for ulcerative colitis?

• A. Sigmoidoscopy is diagnostic
• B. Colonoscopy with biopsy is diagnostic
• C. CT scan of the abdomen is diagnostic
• D. Barium enema is diagnostic

Answer: (A)

Diagnosing ulcerative colitis relies on direct visualization of the colon with tissue sampling. Colonoscopy with biopsy provides both the view of the mucosa and the essential histologic confirmation needed to establish UC, show the continuous inflammation starting at the rectum, and differentiate it from other conditions such as Crohn’s disease or infectious colitis. The biopsy findings—like chronic inflammatory changes and architectural distortion—help confirm the diagnosis and guide management. Sigmoidoscopy examines only the distal colon and may suggest inflammation, but it can miss disease in the rest of the colon and does not provide full histologic confirmation needed for a definitive diagnosis. CT scans and barium enema are not diagnostic for UC; CT can help assess complications or extraintestinal manifestations, and barium studies have mostly been replaced by colonoscopy because they don’t provide the necessary histology and can pose risks in active disease.

Diagnosing ulcerative colitis relies on direct visualization of the colon with tissue sampling. Colonoscopy with biopsy provides both the view of the mucosa and the essential histologic confirmation needed to establish UC, show the continuous inflammation starting at the rectum, and differentiate it from other conditions such as Crohn’s disease or infectious colitis. The biopsy findings—like chronic inflammatory changes and architectural distortion—help confirm the diagnosis and guide management.

Sigmoidoscopy examines only the distal colon and may suggest inflammation, but it can miss disease in the rest of the colon and does not provide full histologic confirmation needed for a definitive diagnosis. CT scans and barium enema are not diagnostic for UC; CT can help assess complications or extraintestinal manifestations, and barium studies have mostly been replaced by colonoscopy because they don’t provide the necessary histology and can pose risks in active disease.