Diagnosis

Tests and procedures used to diagnose pseudomembranous colitis and to search for complications include:

• Stool sample. There are a number of different stool sample tests used to detect C. difficile infection of the colon.
• Blood tests. These may reveal an abnormally high white blood cell count (leukocytosis), which may indicate an infection like C. difficile if you also have diarrhea.
• Colonoscopy or sigmoidoscopy. In both of these tests, your doctor uses a tube with a miniature camera at its tip to examine the inside of your colon for signs of pseudomembranous colitis — raised, yellow plaques (lesions), as well as swelling.
• Imaging tests. If you have severe symptoms, your doctor may obtain an abdominal X-ray or an abdominal CT scan to look for complications such as toxic megacolon or colon rupture.