Abstract
Answer C. Faecal calprotectin
Faecal calprotectin is a marker of intestinal inflammation and can be used to confirm or help exclude a diagnosis of inflammatory bowel disease. Blood tests for C-reactive protein and erythrocyte sedimentation rate can also be used but are non-specific. An abdominal X-ray would not add anything here and a rectal swab is not indicated. A carcinoembryonic antigen blood test is used to monitor colorectal cancer, but is not specific or appropriate to use as a diagnostic test.
InnovAiT article: Lower gastrointestinal bleeding. DOI: 10.1177/1755738017746700.