The evaluation of pseudomembranous colitis begins with a history and physical exam.

Physical findings in someone with pseudomembranous colitis may include:

• Abdominal tenderness
• Abdominal swelling
• Fever
• Rapid pulse

Test are required to make the diagnosis of pseudomembranous colitis.

Tests that may be used to evaluate pseudomembranous colitis include:

• Complete blood count
• Stool cultures
• Stool test for Clostridium difficile
• Colonoscopy
• X-rays of the abdomen
• CT scanning of the abdomen

A stool culture can detect:

• Shigella infection
• Campylobacter enteritis
• Cryptosporidium enterocolitis
• Giardiasis
• Pseudomembranous colitis:
• Clostridium difficile
• Salmonella gastroenteritis
• Traveler's diarrhea due to bacterial infection
• E. coli