What is the Mayo score for Ulcerative Colitis (UC)?

Mayo Score for Ulcerative Colitis

The Mayo Score is a composite 0-12 point scoring system that includes four components: stool frequency (0-3), rectal bleeding (0-3), physician's global assessment (0-3), and endoscopic findings (0-3), widely used in both clinical trials and practice to assess disease activity in ulcerative colitis. 1

Components of the Full Mayo Score

Each of the four components is scored from 0 to 3, with the total score ranging from 0 to 12 1:

Stool Frequency

• 0: Normal number of stools for patient
• 1: 1-2 stools/day more than normal
• 2: 3-4 stools/day more than normal
• 3: 5 or more stools/day more than normal 1

Rectal Bleeding

• 0: No blood seen
• 1: Streaks of blood with stool less than 50% of the time
• 2: Obvious blood with stool most of the time
• 3: Blood alone passed without stool 1

Endoscopic Subscore (Mucosal Appearance)

• 0: Normal or inactive disease
• 1: Mild disease (erythema, decreased vascular pattern, mild friability)
• 2: Moderate disease (marked erythema, absent vascular pattern, friability, erosions)
• 3: Severe disease (spontaneous bleeding, ulceration) 1

Physician's Global Assessment

• 0: Normal
• 1: Mild disease
• 2: Moderate disease
• 3: Severe disease 1

Disease Activity Classification

The total Mayo Score stratifies disease severity 1:

• Mild disease: 3-5 points
• Moderate disease: 6-10 points
• Severe disease: 11-12 points

Clinical Definitions Using Mayo Score

Clinical remission is defined as a total Mayo score ≤2 with no individual subscore >1 1

Clinical response requires a reduction of baseline Mayo score by ≥3 points AND a decrease of ≥30% from baseline score with either a decrease of at least 1 point on the rectal bleeding subscale OR an absolute rectal bleeding score of 0 or 1 1

Mucosal healing is defined as an endoscopic subscore of ≤1 1

Partial Mayo Score

The partial Mayo score uses only the non-invasive components (stool frequency, rectal bleeding, and physician's global assessment), excluding endoscopy, for a maximum of 9 points 1. This correlates well with patient perceptions of response to therapy and is useful for monitoring without requiring endoscopy 1, 2

Clinical Application and Limitations

The Mayo Score is widely used in clinical trials and can be applied to clinical practice as a composite clinical and endoscopic tool 1. The British Society of Gastroenterology recommends using clinical indices such as the partial Mayo score for monitoring remission in combination with other modalities including biomarkers and endoscopy 1

Important caveat: There is wide variation in interpretation of disease activity endoscopically, representing a significant limitation of visual scoring systems 1. The Ulcerative Colitis Endoscopic Index of Severity (UCEIS) was developed to improve reliability and offers greater precision than the Mayo endoscopic subscore, though both remain validated tools 1, 3

The partial Mayo score (6-point score using only stool frequency and rectal bleeding) performs as well as the full Mayo score in identifying patient-perceived clinical response, with a cutpoint of 1.5 demonstrating 88% sensitivity and 80% specificity for patient-defined remission 2