What are the recommended investigations for a patient with suspected ulcerative colitis presenting with diarrhea and abdominal pain?

For a patient presenting with suspected ulcerative colitis with symptoms of diarrhea and abdominal pain, the recommended investigations include:

• Blood tests: Full blood count (FBC) to check for anaemia and inflammatory markers such as erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) to assess inflammation levels.
• Stool tests: To exclude infections and other causes of diarrhea.
• Endoscopic evaluation: Flexible sigmoidoscopy or colonoscopy with biopsy is essential to confirm the diagnosis and assess the extent and severity of mucosal inflammation.
• Additional antibody testing: To exclude other conditions such as coeliac disease if clinically indicated.

These investigations help differentiate ulcerative colitis from other causes of diarrhea and abdominal pain and guide appropriate management.