Mayo Score Calculator for Ulcerative Colitis (Full and Partial Mayo)
Calculate the Mayo score for ulcerative colitis activity — stool frequency, rectal bleeding, endoscopy findings and physician global assessment (0–12) — plus the partial Mayo score without endoscopy.
How it works
Mayo score = stool frequency (0–3) + rectal bleeding (0–3) + endoscopy (0–3) + physician global assessment (0–3); range 0–12. Remission: ≤ 2 with no subscore above 1 · mild 3–5 · moderate 6–10 · severe 11–12. Partial Mayo = the same without endoscopy (0–9).
The Mayo score (Schroeder et al., New England Journal of Medicine 1987) is the standard disease-activity index in ulcerative colitis clinical trials and is widely used in clinics. Stool frequency is judged against the patient’s own normal, and bleeding is the most severe seen that day. Clinical response is usually a fall of at least 3 points and 30% from baseline with a fall in bleeding; the partial (non-invasive) Mayo score is used to follow patients between endoscopies.
Worked example
A patient has 3–4 extra stools a day (2), streaks of blood less than half the time (1), moderate endoscopic disease with erosions (2) and the doctor rates the disease as moderate (2): Mayo score = 2 + 1 + 2 + 2 = 7 / 12 — moderate activity; partial Mayo score 5 / 9.
Sources: Schroeder KW et al. Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. N Engl J Med 1987 · Lewis JD et al. Use of the noninvasive components of the Mayo score to assess clinical response in ulcerative colitis. Inflamm Bowel Dis 2008
Frequently asked questions
What Mayo score means remission?
A total of 2 or less with no individual subscore above 1 is the usual definition of clinical remission; many trials also require a rectal bleeding subscore of 0 and an endoscopic subscore of 0 or 1.
What is the partial Mayo score?
The Mayo score without the endoscopy item, scored 0–9. It tracks symptoms between colonoscopies; 2 or less is commonly taken as remission.
What is an endoscopic Mayo score of 2?
Moderate disease: marked redness, loss of the normal vascular pattern, friability and erosions. A Mayo endoscopic subscore of 0–1 is the usual target of treatment (mucosal healing).
How is stool frequency scored?
Against the person’s own normal number of daily stools when well — 1–2 more is 1 point, 3–4 more is 2 and 5 or more is 3.
Related calculators
Clinical decision tool for education and for use by trained clinicians alongside clinical judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.