What Makes a High-Quality Colonoscopy?

Preparation is a quality intervention

If mucosa cannot be seen, lesions cannot be detected. The 2024 quality statement increased the target for adequate preparation to 90%, and 2025 bowel-preparation recommendations emphasize split dosing and practical regimen optimization. Preparation quality should be documented using a validated scale after washing and suctioning.

Cecal intubation must be documented

Complete examination requires intubation of the cecum with photographic documentation of landmarks. High completion rates are expected in routine practice. Incomplete examinations need a documented plan for repeat colonoscopy or alternative complete colonic evaluation.

Detection metrics matter

ADR is one of the strongest endoscopist-level quality metrics because higher ADR is associated with lower post-colonoscopy colorectal cancer risk. The updated benchmark is >35% for screening, surveillance and diagnostic colonoscopies in eligible adults older than 45. Sessile serrated lesion detection is now separately emphasized because missed proximal serrated lesions contribute to interval cancers.

Withdrawal is active inspection

Withdrawal time is not a timer game. Adequate time allows washing, fold examination, position change, re-examination of difficult segments and careful evaluation of subtle lesions. The updated quality target increased average withdrawal time in normal examinations without biopsy to more than 8 minutes.

Resection and recommendation complete the quality cycle

Small polyps should be removed using evidence-based techniques; cold snare is favored for 4-9 mm lesions. The procedure report should document completeness and assign the next screening or surveillance interval based on pathology, examination quality and guideline criteria. An excellent examination followed by an incorrect interval is still a quality failure.

A practical clinical approach

1. Confirm an appropriate indication and informed consent.
2. Use split-dose bowel preparation and document adequacy after cleaning.
3. Reach and photograph the cecum whenever anatomically possible.
4. Inspect deliberately with an average withdrawal time consistent with quality benchmarks.
5. Track ADR and sessile serrated lesion detection at the endoscopist level.
6. Use safe evidence-based resection techniques and retrieve pathology when required.
7. Give a guideline-concordant follow-up interval and document the rationale.

Common errors to avoid

• Treating withdrawal time as a substitute for inspection quality.
• Failing to measure personal ADR.
• Calling a preparation 'fair' without stating whether it was adequate for assigning the standard interval.
• Ignoring sessile serrated lesion detection.
• Giving surveillance intervals before pathology is available when pathology could change the recommendation.

What should trainees remember?

High-quality colonoscopy is a system of measurable behaviors. Detection quality, not procedural speed or technology ownership, is the defining outcome.

Free further reading from Dr. Alan B. R. Thomson

See Dr. Thomson's Endoscopy and Diagnostic Imaging and Best Practice Guidelines in Gastroenterology Disorders.

Frequently asked questions

What is the updated ADR benchmark?

The 2024 ACG/ASGE statement identifies >35% as a priority target in the defined eligible population.

What is the target for adequate bowel preparation?

>90% when coupled with an appropriate follow-up recommendation.

How long should withdrawal take?

Average withdrawal time in normal colonoscopies without biopsy should be more than 8 minutes under the updated quality indicators.

References

1. Thomson ABR. Endoscopy and Diagnostic Imaging, Parts I-II. CAPstone Academic Publishers; 2012. ISBN 978-1477400579 and 978-1477400654.

2. Thomson ABR. Best Practice Guidelines in Gastroenterology Disorders. CAPstone Academic Publishers; 2024. ISBN 979-8398710120.

3. Rex DK, et al. Quality Indicators for Colonoscopy. ACG/ASGE Position Statement. Am J Gastroenterol. 2024.

4. Schoenfeld P. Quality Indicators for Colonoscopy: New Targets… But Will They Be Measured? Evidence-Based GI. 2024.

5. US Multi-Society Task Force on Colorectal Cancer. Optimizing Bowel Preparation Quality for Colonoscopy. 2025.