| Score | Decoding |
| 0 - 2 | remission (provided that no subscore for each single parameter is greater than 1) |
| 3 - 5 | mild activity |
| 6 - 10 | moderate activity |
| > 10 | severe activity |
Note: if the total score is 2, but achieved with only one subscore = 2 and the other three = 0, the computer gives as a result the score 2 and the sentence: mild activity (single subscore = 2).
To calculate the score you need to fill in all fields, with a single selection menu. The Mayo endoscopic subscore is calculated on the more serious injuries observed, by evaluating at least the rectum and sigmoid colon, better if also including the descending colon.
Mayo 0 degree is to be attributed both in case of normality or in case of reparative lesions (scarring or pseudopolyps): in case of presence of pseudopolyps and/or mucosal bridges, to assign the score you need to consider only the flat mucosa interposed (hyperemia and erosions not to be considered if localized only on pseudopolyps).
Mayo 1 degree is characterized by mild inflammation, but substantial, with distortion of the vascular network (not entirely disappeared), focal hyperemia and edema, contact frailty and at maximum 1 single erosion (mucosal break >5 mm).
Mayo 2 degree is identified when at least 2 erosions are present; diffuse erythema and disappearance of the vascular network may or may not also be present.
Mayo 3 degree is given whenever there is at least one ulcer or spontaneous bleeding in a segment.
The presence of deep ulcers, which have prognostic importance, should be considered separately.
| Mayo 0 normal mucosa or inactive disease | ![]() ![]() ![]() |
| Mayo 1 mild disease (erythema, decreased vascular pattern, mild friability) | ![]() ![]() ![]() |
| Mayo 2 moderate disease (marked erythema, lack of vascular pattern, friability, erosions) | ![]() ![]() ![]() |
| Mayo 3 severe disease (spontaneous bleeding, large ulcerations) | ![]() ![]() ![]() |