Dr. med. Dörte Wichmann

Recommended documentation for the quality of bowel preparation

Various measures introduced in recent decades have led to a reduction in the mortality rate due to colorectal carcinoma. They include screening colonoscopy, which was introduced in Germany in late 2002 with coverage by statutory health insurance and is currently available to men starting from age 50 and women starting from age 55.

The successful performance and diagnostic power of colonoscopy are mainly influenced by the quality of bowel preparation. In its consensus-based Level 2 (S2k) guideline on “Quality Requirements in Flexible Endoscopy,” the German Association for Gastroenterology, Digestive and Metabolic Diseases (Deutsche Gesellschaft für Gastroenterologie, Verdauungs- und Stoffwechselkrankheiten, DGVS) recommends documenting the quality of preparation in the examination report, and refers to the Boston Bowel Preparation Scale (BBPS) as a suitable method for classifying the assessment [1].

The BBPS is a standardized 9-point assessment scale for the colon. The structure of the colon is divided into its three segments: right colon, transverse colon, and left colon. Each segment is classified from 0 to 3 depending on the degree of soiling. The sum total of the three segments represents the degree of soiling, so that a total ≤ 5 points shows poor bowel preparation, while 6–7 shows good bowel preparation, and ≥ 8 very good bowel preparation.

In their analysis, Lai et al. showed that the BBPS is an easy to learn and practicable method [2]. The BBPS was first published in 2009 and is the scale most often used worldwide to describe the degree of bowel preparation. The practicability and validity of the BBPS have been evaluated in several studies, and it has good inter-observer and intra-observer reliability (κ = 0.78; 95% CI, 0.73 to 0.84) [3].

Grade      Grade Endoscopic findings
0Represents an unprepared colon segment. The mucosa is not visible due to solid feces, and the fecal masses cannot be removed.
1Parts of the mucosa in the colon segment can be seen, but other areas of the same segment cannot be seen well due to blockage with stool and/or opaque liquid.
2The mucosa of the colon segment can be seen well, with minor amounts of residual stool, small fragments of stool and/or opaque liquid.
3The entire mucosa of the colon segment can be seen well, with no residual soiling.
Table 1 The Boston Bowel Preparation Scale

The BBPS should be presented in the examination report using the following documentation: right / transverse / left; e.g. = 3/2/3, along with the corresponding total (BBPS = 8).

Lai et al. report a significantly poorer adenoma detection rate when there is poor bowel preparation (BBPS ≤ 5) in comparison with a good preparation score (BBPS > 5) [2]. However, it has not been confirmed that there is an improved adenoma detection rate between the preparation qualities “good” (2) and “very good” (3) [4]. As a result, the S2k guideline “Quality Requirements in Gastrointestinal Endoscopy” recommends the use of a simplified BBPS, stating the grade for the poorest segment [1]. The guideline also notes that the adenoma detection rate is used as the major surrogate parameter for the outcome quality of a colonoscopy. When there is poor bowel preparation, corresponding to a BBPS of ≤ 5 or a simplified BBPS of ≤ 1, it is recommended that the colonoscopy should be repeated.

The findings may be documented as running text or as individual points.

Findings corresponding to BBPS 0
Findings corresponding to BBPS 1
Findings corresponding to BBPS 2
Findings corresponding to BBPS 3


  1. Denzer U, Beilenhoff U, Eickhoff A, et al. [S2k guideline: quality requirements for gastrointestinal endoscopy, AWMF registry no. 021-022]. Z Gastroenterol 2015;53(12):E1–227. German. doi: 10.1055/s-0041-109598.
  2. Lai EJ, Calderwood AH, Doros G, et al. The Boston bowel preparation scale: a valid and reliable instrument for colonoscopy-oriented research. Gastrointest Endosc 2009;69(3 Pt 2):620–5. doi: 10.1016/j.gie.2008.05.057.
  3. Calderwood AH, Schroy PC 3rd, Lieberman DA, et al. Boston Bowel Preparation Scale scores provide a standardized definition of adequate for describing bowel cleanliness. Gastrointest Endosc 2014;80(2):269–76. doi: 10.1016/j.gie.2014.01.031.
  4. Mahadev S, Green PH, Lebwohl B. Rates of suboptimal preparation for colonoscopy differ markedly between providers: impact on adenoma detection rates. J Clin Gastroenterol 2015;49(9):746–50. doi: 10.1097/MCG.0000000000000210.

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