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Copyright ©The Author(s) 2018.
World J Gastroenterol. Jul 14, 2018; 24(26): 2833-2843
Published online Jul 14, 2018. doi: 10.3748/wjg.v24.i26.2833
Table 1 Validated bowel preparation scales
Scale nameScoreRating/descriptionOther scale properties/characteristics
Aronchick Scale1Excellent: Small volume of liquid; > 95% of mucosa seenTotal score range: Minimum 1 (excellent) to maximum 5 (inadequate) Scoring performed before washing or suctioning No separate ratings for segments; global colon rating only No threshold for adequate/inadequate provided
2Good: Clear liquid covering 5%-25% of mucosa, but > 90% of mucosa seen
3Fair: Semisolid stool could not be suctioned or washed away, but > 90% of mucosa seen
4Poor: Semisolid stool could not be suctioned or washed away and < 90% of mucosa seen
5Inadequate: Repeat preparation/screening needed
Ottawa Bowel Preparation Scale (by colon segment)0Excellent: Mucosal detail clearly visible, almost no stool residue; if fluid present, it is clear, almost no stool residueTotal score (obtained by adding scores for each segment + total colon fluid score) range: Minimum 0 (excellent) to maximum 14 (inadequate) Scoring performed before washing or suctioning Rates cleansing by colon segment: Right colon, mid-colon, and rectosigmoid colon (Figure 1) No threshold for adequate/inadequate provided
1Good: Some turbid fluid or stool residue, but mucosal detail still visible without need for washing/suctioning
2Fair: Some turbid fluid of stool residue obscuring mucosal detail; however, mucosal detail becomes visible with suctioning, washing not needed
3Poor: Stool present obscuring mucosal detail and contour; a reasonable view is obtained with suctioning and washing
4Inadequate: Solid stool obscuring mucosal detail and not cleared with washing and suctioning
Ottawa Bowel Preparation Scale (total colon fluid)0Small amount of fluidTotal colon fluid score range: Minimum 0 (small amount of fluid) to maximum 2 (large amount of fluid) Scoring performed before washing or suctioning Single score for the total colon No threshold for adequate/inadequate provided
1Moderate amount of fluid
2Large amount of fluid
Boston Bowel Preparation Scale (by colon segment)0Unprepared colon segment with mucosa not seen because of solid stool that cannot be clearedTotal score (obtained by adding scores for each segment) range: Minimum 0 (very poor) to maximum 9 (excellent) Scoring performed after washing or suctioning Segments separately rated: Right colon (including cecum and ascending colon); transverse (includes hepatic and splenic flexures); and left colon (descending and sigmoid colon, and rectum) Threshold optimally is total score of ≥ 6 AND ≥ 2 per segment
1Portion of mucosa of the colon segment seen, but other areas of segment not well seen because of staining, residual stool, and/or opaque liquid
2Minor amount of residual staining, small fragments of stool, and/or opaque liquid, but mucosa of colon segment is well seen
3Entire mucosa of colon segment well seen, with no residual staining, small fragments of stool, or opaque liquid
Harefield Cleansing Scale (by colon segment)0Irremovable, heavy, hard stoolsTotal score (obtained by adding scores for each segment) range: Minimum 0 (very bad) to maximum 20 (very good) Scoring performed after washing or suctioning Segments separately rated: Rectum, sigmoid, left, transverse, right colon Threshold for successful cleansing = Grade A: no segment scored < 3 or 4, or Grade B: ≥ 1 segment scored 2 but no segment < 2; Unsuccessful cleansing = Grade C: ≥ 1 segment scored 1 but no segment < 1, or Grade D: ≥ 1 segment scored 0
1Semisolid, only partially removable stools
2Brown liquid/fully removable semi-solid stools
3Clear liquid
4Empty and clean
Chicago Bowel Preparation Scale (by colon segment)0Unprepared colon segment with stool that cannot be cleared (> 15% of mucosa not seen)Total score (obtained by adding scores for each segment) range: Minimum 0 (unprepared) to maximum 36 (excellent) Scoring performed before (fluid) and after (mucosal cleaning) washing or suctioning Segments separately rated: Right (cecum to mid-hepatic flexure), transverse (mid-hepatic flexure to mid-splenic flexure), and left colon (mid-splenic flexure to distal rectum) No threshold for adequate/inadequate provided
5Portion of mucosa in segment seen after cleaning, but up to 15% of the mucosa not seen because of retained material
10Minor residual material after cleaning, but mucosa of segment generally well seen
11Entire mucosa of segment well seen after washing
12Entire mucosa of segment well seen before washing or suctioning
Chicago Bowel Preparation Scale (total colon)0Little fluid (≤ 50 cc)Total score range: Minimum 0 (little fluid) to maximum 3 (large amount of fluid) Scoring performed before washing or suctioning No threshold for adequate/inadequate provided Not incorporated into total score for segments
1Minimal amount of fluid (51-150 cc)
2Moderate amount of fluid (151-300 cc)
3Large amount of fluid (> 300 cc)
Table 2 Reliability and validation data for bowel preparation scales
ScaleStudyColons (n)Raters (n)ReliabilityValidity
AronchickAronchick[41], 2004805ICC values for: Total colon: 0.77 Cecum: 0.76 Distal colon: 0.31NR
OBPSRostom et al[50], 2004972ICC values for: Right colon: 0.92 Mid colon: 0.88 Rectosigmoid colon: 0.89Comparisons with Aronchick scale PCC: 0.89 OBPS vs 0.62 Aronchick ICC: 0.94 OBPS vs 0.77 Aronchick
Chan et al[53], 2011211NRNRCutoff scores for adequacy/inadequacy Optimal cutoff for inadequate ≥ 8: Sensitivity, 100%, specificity, 91%
Martinato et al[54], 2013150NRRatings of physicians vs nurses: PCC: r = 0.60Correlations with VAS PCC (physicians vs nurses): r = 0.60
Lee et al[58], 2016655NANRComparison with BBPS for PDR and ADR PCC: r = -0.62 (P < 0.001); AUC of ROC analysis similar for PDR, ADR, right-sided adenomas, and SSAs
BBPSLai et al[47], 200963322ICC values: 0.74/0.77 wtd κPDR by score 40% for scores ≥ 5 vs 24% for scores < 5 (P < 0.02) Need for repeat CSP due to inadequate bowel prep 2% for scores ≥ 5 vs 73% for scores < 5 (P < 0.001) Correlation with colonoscope insertion time PCC: r = -0.16 (P < 0.003) Correlation with colonoscope withdrawal time PCC: r = -0.23 (P < 0.001)
Calderwood et al[43], 201011912ICC values for: Total colon: 0.91 Right colon: 0.88 Transverse colon: 0.83 Left colon: 0.79Correlations with ability to exclude polyps > 5 mm 100%, 88%, 82%, 33%, and 0% of physicians deemed bowel preparation adequate to exclude polyps > 5 mm at scores of ≥ 8, 7, 6, 5, and ≤ 4 respectively Correlations with surveillance recommendations after normal CSP Score < 5: 100% recommended ≤ 1 yr Scores 5-6: mean recommended interval 4.3 (± 3.9) yr Scores ≥ 7: 100% recommended 10 yr
Calderwood et al[44], 2014251674NRPhysician-recommended CSP interval after negative CSP Scores ≥ 6 (≥ 2 each segment): 90% recommended 10 yr Scores 0-2: 96% recommended ≤ 1 yr
Schindler et al[49], 20163401ICC values, all raters (all segment and total scores): 0.93NR
Gao et al[45], 2013101213ICC values: 0.987/0.671 wtd κPDR Scores ≥ 5 superior vs < 5 (35% vs 18%; P < 0.05)
Kim et al[46], 20144826ICC values: Total colon: 0.90/0.63 wtd κ Right colon: 0.93/0.91 wtd κ Transverse colon: 0.88/0.86 wtd κ Left colon: 0.50/0.38 wtd κPDR Scores ≥ 8 superior vs scores < 8 (44.9% vs 33.0%; P = 0.04) Colonoscope withdrawal time PCC: r = -0.167 (P < 0.001) Colonoscope insertion time PCC: r = 0.018 (P = 0.695)
Clark et al[57], 20164384ICC values by BBPS scores: 0 and 3: 1.0 2: 0.81 1: 0.80ADR (> 5 mm) miss rates by BBPS score: 3: 5.6% 2: 5.2% 1: 15.9% Score of 2 noninferior to 3 for missed adenoma > 5 mm
HCSHalphen et al[51], 20133374ICC value: 0.457 Test-retest κ values: Range, 0.33 to 0.85 Intrarater2: 0.28 to 0.64 Internal consistency3: 0.81, 0.86Best score cutoff for satisfactory bowel preparation ≥ 2 for each segment: Sensitivity, 99% and specificity, 83% Correlation with Aronchick scale PCC: r = 0.833 AUC of ROC analysis (vs Aronchick scale scores) 0.945 for total colon
CBPSGerard et al[52], 201315044ICC values for: Range, 0.624 to 0.702 for all segmentsCorrelations of scores with adequate cleansing Adequate: Scores of 25-36 (≥ 95% of mucosa visualized) Inadequate: Scores of 0-24 (< 95% of mucosa visualized)