Reducing failed endoscopy procedures through improved pre-assessment

Setting / patient group: Endoscopy service. The project focused on patients undergoing colonoscopy, including those undergoing combined upper and lower GI endoscopy procedures.  

Issue

Review of activity between January and April 2026 identified 167 colonoscopies that failed due to inadequate bowel preparation, representing 11% of procedures. Failure rates were particularly high among patients undergoing combined procedures, where 22% failed due to poor bowel preparation. Failed procedures result in repeat investigations, delays to diagnosis, additional patient burden, increased costs and avoidable environmental impact. The department was not meeting the Joint Advisory Group (JAG) benchmark relating to unsuccessful procedures.

Intervention

The team mapped the lower GI endoscopy pathway, reviewed factors contributing to inadequate bowel preparation, and redesigned the pre-assessment process. Key changes included:

• Introduction of one-stop face-to-face pre-assessment clinics.
• Implementation of a nurse-led Patient Group Directive (PGD) allowing bowel preparation to be supplied directly by the Endoscopy Department during pre-assessment.
• Increased use of the lower-volume Plenvu bowel preparation regimen in place of Moviprep. 
• Replacement of paper consent processes with electronic consent and digital patient information.

Outcomes

Clinical

• Colonoscopy failure due to inadequate bowel preparation reduced from 11% (167 procedures) to 7% (64 procedures).
• Failure rates for standalone colonoscopies reduced to 5%.
• The department achieved compliance with the JAG benchmark of fewer than 10% unsuccessful procedures.
• The proportion of failed procedures requiring repeat investigation fell from 47% to 34%.
• Additional waiting time for patients requiring repeat procedures reduced from an average of 41 days to 26 days.
• The reduction in repeat procedures released approximately 4.2 endoscopy sessions per month.

Environmental

An estimated 3,024 kgCO₂e saved per year through reducing failed colonoscopies and avoiding unnecessary repeat procedures.

Financial
An estimated £222,296 saved per year through reducing failed colonoscopies due to inadequate bowel preparation 

Social

• More than 97% of patients and 93% of staff agreed that it is important for the NHS to minimise cost and waste, even if this is sometimes less convenient.
• 90% patients who required combined procedures preferred having both procedures undertaken during a single appointment, citing reduced travel, reduced time away from work and less anxiety.
• Staff identified that combined procedures can present challenges for patients because bowel preparation and fasting requirements are more complex.
• Face-to-face pre-assessment was perceived as providing better opportunities for personalised education and support. 

Further improvements

The team identified combined upper and lower GI procedures as the main remaining area for improvement due to persistently higher failure rates. Proposed next steps include testing simplified, appointment-specific instructions, reminder text messages, and reviewing procedure scheduling to improve bowel preparation compliance. The team also identified opportunities to reduce waste associated with Senna dispensing, procedural water use and sedation vial sizes.

Key learning point

The project demonstrated that a face-to-face, one-stop pre-assessment pathway can improve bowel preparation outcomes, reduce repeat procedures and deliver environmental and financial benefits. However, introducing multiple changes simultaneously made it difficult to determine which intervention had the greatest impact. The project also highlighted the importance of studying service pathways in detail, as procedures assumed to be more efficient, such as combined upper and lower GI endoscopy, may still generate waste and inefficiency when failure rates are high.