Diagnostic yield of colonoscopy based on symptoms.

Objective: There are only a few data on the diagnostic yield of colonoscopy in different symptoms. The aim of this study was to assess the outcome of colonoscopy in patients with various gastrointestinal symptoms and to estimate the relation between the findings and the presenting symptoms.

Material And Methods: 1121 consecutive colonoscopies were registered during 1 year. Asymptomatic subjects and patients with known inflammatory bowel disease (IBD) were excluded, leaving 767 eligible for the study. Symptoms, findings and clinical judgement about their relation were recorded.

Results: In patients with bleeding symptoms (n=405), serious colonic pathology--cancers and adenomas >1 cm, IBD and angiodysplasia--was found in 54 (13.3%), 83 (20.5%) and 20 (4.9%) patients, respectively; 162 (40%) patients had findings that could be related to the symptom. In 173 subjects with non-bloody diarrhoea, the diagnostic yield was 31.2%, i.e. mostly IBD and microscopic colitis. In 189 subjects with other gastrointestinal symptoms, the diagnostic yield was 13.2%. Serious colonic pathology was found in 8 of 362 (2.2%) subjects examined because of non-bleeding symptoms.

Conclusion: The diagnostic yield of colonoscopy is high in patients with bleeding symptoms or diarrhoea, while the prevalence of significant findings is equal to a screening population in patients with other symptoms.