Figure 1. Ottawa Scale
Evaluation
Table 2. Boston Bowel Preparation Scale
0 Unprepared colon segment with mucosa not seen because of solid stool that cannot
be cleared.
1
Portion of mucosa of the colon segment seen, but other areas of the colon segment are
not well seen because of staining, residual stool, and/or opaque liquid.
2
Minor amount of residual staining, small fragments of stool, and/or opaque liquid,
but mucosa of colon segment is seen well.
3
Entire mucosa of colon segment seen well, with no residual staining, small fragments
of stool, or opaque liquid.
e Ottawa bowel preparation quality scale use guide.
(1) Part A of the scale is applied to each colon segment: right colon (Right), midcolon (Mid),
and the rectosigmoid colon (Recto-Sigmoid). (2) e fluid quantity is a global value for the
entire colon. (3) e score is calculated by adding the ratings of 0–4 for each colon segment and
the fluid quantity rating of 0–2. (4) e scale has a range from 0 (perfect) to 14 (solid stool in
each colon segment and lots of fluid; ie, a completely unprepared colon). (5) Before using the
scale in a study or audit, observers need to perform a calibration exercise.
