Adenoma detection in the main goal of screening colonoscopy. In order to detect adenomas it is mandatory to spend a long enough time investigating the colonic mucosa. A minimum observation time of 6 minutes has been proposed as a quality criterion for screening colonoscopy. However, different locations of the colon (proximal, distal) may require specific observation time periods. The colon can be divided into a proximal (right) and distal (left) part. Until now, it is unclear whether observation time has a significant impact on adenoma detection in both parts of the colon. The aim of this study therefore is to conduct a trial in which side-specific observation times and adenoma detection rates are measured in order to investigate this correlation in particular for the right colon.

Inclusion Criteria:

• indication for colonoscopy
• age ≥ 40 years

Exclusion Criteria:

• American Society of Anesthesiologists class IV or higher
• pregnant women
• indication for colonoscopy: inflammatory bowel disease
• indication for colonoscopy: polyposis syndrome
• indication for colonoscopy: emergency colonoscopy e.g. acute bleeding
• contraindication for polyp resection e.g. patients on warfarin

Patients receiving colonoscopy at the study site are eligible for participation.