The Mayo score describes how active ulcerative colitis is. It was published in 1987 and has four items, each scored 0 to 3, so the total runs from 0 to 12. Three of them make up the partial Mayo score, which you can work out at an ordinary appointment: stool frequency, rectal bleeding and the doctor’s overall assessment. The fourth needs a colonoscopy or sigmoidoscopy, so this page has no calculator.
The colonoscopy item
At the colonoscopy, the doctor scores what the lining of the bowel looks like:
- 0: normal, or inactive disease.
- 1 (mild): redness, fewer visible blood vessels, and lining that bleeds slightly when touched.
- 2 (moderate): marked redness, no visible blood vessels, lining that bleeds easily, and small breaks in the lining (erosions).
- 3 (severe): bleeding without being touched, and ulcers.
The modified Mayo score
Newer trials often use a modified Mayo score, which the US Food and Drug Administration’s draft guidance for ulcerative colitis trials describes. It keeps stool frequency, rectal bleeding and the colonoscopy item but drops the doctor’s overall assessment, so it runs from 0 to 9, and a colonoscopy score of 1 no longer includes bleeding when touched. Because the two versions are scored differently, a full Mayo score and a modified Mayo score for the same visit aren’t directly comparable.
The partial Mayo page shows how medicines rules in your country use the score.
Sources
- Schroeder KW, Tremaine WJ, Ilstrup DM. Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. N Engl J Med 1987;317(26):1625-1629
- US Food and Drug Administration. Ulcerative colitis: developing drugs for treatment (draft guidance, April 2022), appendix: the modified Mayo score