What is the PRO-2 score in ulcerative colitis?

PRO-2 is a two-item patient-reported score made from the stool frequency and rectal bleeding parts of the Mayo Clinic Score. Each item is scored 0 to 3, so the total runs from 0 to 6.

What PRO-2 score counts as remission?

The most widely used definition is a rectal bleeding subscore of 0 plus a stool frequency subscore of 0 or 1. Some trials require a stool frequency subscore of 0, and some allow up to 2.

How is the stool frequency subscore worked out?

It compares your current stools a day with your own normal: 0 for your normal number, 1 for one to two more, 2 for three to four more and 3 for five or more. It is not a raw count.

Does a PRO-2 of 0 mean my colon has healed?

Not reliably. In one large trial analysis, having both subscores at 0 predicted a mildly inflamed or normal lining in about 90% of people but a completely normal lining in only 46%, so it is usually paired with calprotectin or a scope.

Is PRO-2 the same as the Mayo score?

No. The full Mayo Clinic Score also includes an endoscopy reading and a clinician's assessment and runs from 0 to 12. PRO-2 is only the two items you report yourself.

Why is my stool frequency still raised when I have no bleeding?

This is common. Among people whose lining looked completely normal in one trial analysis, only 29% reported a normal stool frequency at week 8, and long-term changes in the bowel can keep stool counts up after inflammation settles.

Does PRO-2 include urgency?

No. Urgency, abdominal pain, tiredness and night-time stools are not in PRO-2, so it is worth recording them alongside it if they affect you.

PRO-2 Score Calculator for Ulcerative Colitis

Score the two symptoms UC trials use to define remission.

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Updated October 3, 2026

The short answer

The PRO-2 score for ulcerative colitis adds two items from the Mayo Clinic Score: a stool frequency subscore from 0 to 3, based on how many more stools you pass than your normal, and a rectal bleeding subscore from 0 to 3. The total runs from 0 to 6. The most widely used definition of remission is a bleeding subscore of 0 with a stool frequency subscore of 0 or 1, though trials vary.

How to use the PRO-2 Score Calculator for Ulcerative Colitis

1Enter how many stools a day you usually pass when you are well.
2Enter your average number of stools a day over the last 3 days.
3Choose the option that best describes any rectal bleeding over those days.
4Get your stool frequency and bleeding subscores, your PRO-2 total out of 6 and whether you meet the common remission definition.

How the PRO-2 score is calculated

PRO-2 was developed in 2015 as an interim patient-reported measure for ulcerative colitis drug trials. It takes the two items you report yourself from the Mayo Clinic Score, first used in a 1987 trial, and leaves out the endoscopy reading and the clinician's overall assessment.

The stool frequency item is scored against your own normal, not as a raw count, so two people with the same number of stools can score differently. In trials both items are recorded in a daily diary and averaged over about three days.

Score	Stool frequency subscore	Rectal bleeding subscore
0	Normal number of stools for you	No blood seen
1	1 to 2 stools more than normal	Streaks of blood with stool less than half the time
2	3 to 4 stools more than normal	Obvious blood with stool most of the time
3	5 or more stools more than normal	Blood alone passed

What your score means

PRO-2 has no published mild, moderate or severe bands. What it is used for is a remission yes or no, and even that is not one agreed number: a review of ulcerative colitis trials found more than 50 different definitions of response or remission. The definition below is the one used most often.

Bleeding is the sharper of the two items. Across studies, having no rectal bleeding identifies a quiet colon more reliably than a normal stool count, and a stool count slightly above normal is common even when the lining looks healed. Our guide to the PRO-2 score in ulcerative colitis explains why.

Definition	Bleeding subscore	Stool frequency subscore
Most common remission definition	0	0 or 1
Looser version tested in the original paper	0	0 to 2
Strictest version	0	0 (total of 0)

PRO-2 is not the Mayo score

At least four different numbers get called a Mayo score. If a clinic letter quotes one, it is worth asking which it is.

PRO-2 also means something different in Crohn's disease, where it pairs stool frequency with abdominal pain. For Crohn's, the Harvey-Bradshaw Index calculator is the closer equivalent.

Name	What it includes	Range
Full Mayo Clinic Score	Stool frequency, rectal bleeding, endoscopy, clinician's assessment	0 to 12
Partial Mayo score	The same without endoscopy	0 to 9
Mayo endoscopic subscore	Appearance of the lining at a scope	0 to 3
PRO-2	Stool frequency and rectal bleeding	0 to 6

Frequently asked questions

What is the PRO-2 score in ulcerative colitis?: PRO-2 is a two-item patient-reported score made from the stool frequency and rectal bleeding parts of the Mayo Clinic Score. Each item is scored 0 to 3, so the total runs from 0 to 6.
What PRO-2 score counts as remission?: The most widely used definition is a rectal bleeding subscore of 0 plus a stool frequency subscore of 0 or 1. Some trials require a stool frequency subscore of 0, and some allow up to 2.
How is the stool frequency subscore worked out?: It compares your current stools a day with your own normal: 0 for your normal number, 1 for one to two more, 2 for three to four more and 3 for five or more. It is not a raw count.
Does a PRO-2 of 0 mean my colon has healed?: Not reliably. In one large trial analysis, having both subscores at 0 predicted a mildly inflamed or normal lining in about 90% of people but a completely normal lining in only 46%, so it is usually paired with calprotectin or a scope.
Is PRO-2 the same as the Mayo score?: No. The full Mayo Clinic Score also includes an endoscopy reading and a clinician's assessment and runs from 0 to 12. PRO-2 is only the two items you report yourself.
Why is my stool frequency still raised when I have no bleeding?: This is common. Among people whose lining looked completely normal in one trial analysis, only 29% reported a normal stool frequency at week 8, and long-term changes in the bowel can keep stool counts up after inflammation settles.
Does PRO-2 include urgency?: No. Urgency, abdominal pain, tiredness and night-time stools are not in PRO-2, so it is worth recording them alongside it if they affect you.

PRO-2 Score in Ulcerative Colitis: What It Means
PRO-2 is two Mayo score items, stool frequency and rectal bleeding, each 0-3, totalling 0-6. What the number means, what it misses, and how to read it.
How to Know If Your Ulcerative Colitis Is Flaring
A flare means active inflammation, not just a bad week. How to compare today with your own baseline, score yourself, and know when a test is needed.
Ulcerative Colitis Symptoms While in Remission
Still getting urgency, soft stools or cramps after being told you are in remission? What that usually means, what to get checked, and what the research shows.
How to Stop Urgency With Ulcerative Colitis
Bowel urgency in UC comes from a stiff, hypersensitive rectum, not weak willpower. What reduces it, why it lags behind healing, and what to ask for next.
What Calprotectin Levels Mean in Ulcerative Colitis
A calprotectin number is a concentration, not a severity score. What the value means in UC, why the same stool gives different numbers, and which thresholds matter.

Sources

Jairath V, Khanna R, Zou GY, Stitt L, Mosli M, Vandervoort MK, et al. Development of interim patient-reported outcome measures for the assessment of ulcerative colitis disease activity in clinical trials. Aliment Pharmacol Ther. 2015;42(10):1200-10. doi:10.1111/apt.13408
Schroeder KW, Tremaine WJ, Ilstrup DM. Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. A randomized study. N Engl J Med. 1987;317(26):1625-9. doi:10.1056/NEJM198712243172603
Dragasevic S, Sokic-Milutinovic A, Stojkovic Lalosevic M, Milovanovic T, Djuranovic S, Jovanovic I, et al. Correlation of patient-reported outcome (PRO-2) with endoscopic and histological features in ulcerative colitis and Crohn's disease patients. Gastroenterol Res Pract. 2020;2020:2065383. doi:10.1155/2020/2065383
Jharap B, Sandborn WJ, Reinisch W, D'Haens G, Robinson AM, Wang W, et al. Randomised clinical study: discrepancies between patient-reported outcomes and endoscopic appearance in moderate to severe ulcerative colitis. Aliment Pharmacol Ther. 2015;42(9):1082-92. doi:10.1111/apt.13387
Golovics PA, Gonczi L, Reinglas J, Verdon C, Pundir S, Afif W, et al. Patient-reported outcome and clinical scores are equally accurate in predicting mucosal healing in ulcerative colitis: a prospective study. Dig Dis Sci. 2022;67(7):3089-95. doi:10.1007/s10620-021-07178-w
Ma C, Panaccione R, Fedorak RN, Parker CE, Nguyen TM, Khanna R, et al. Heterogeneity in definitions of endpoints for clinical trials of ulcerative colitis: a systematic review for development of a core outcome set. Clin Gastroenterol Hepatol. 2018;16(5):637-647.e13. doi:10.1016/j.cgh.2017.08.025
Restellini S, Chao CY, Martel M, Barkun A, Kherad O, Seidman E, et al. Clinical parameters correlate with endoscopic activity of ulcerative colitis: a systematic review. Clin Gastroenterol Hepatol. 2019;17(7):1265-1275.e8. doi:10.1016/j.cgh.2018.12.021
Fierens L, Carney N, Novacek G, van der Woude CJ, Siegmund B, Casellas F, et al. A core outcome set for inflammatory bowel diseases: development and recommendations for implementation in clinical practice through an international multi-stakeholder consensus process. J Crohns Colitis. 2024;18(10):1583-95. doi:10.1093/ecco-jcc/jjad195

Cite this tool

Clairop. PRO-2 Score Calculator for Ulcerative Colitis. www.clairop.com/tools/pro-2-score-calculator. Updated October 3, 2026.

Clairop is a general wellness app for people living with a diagnosed digestive condition. It does not replace professional medical care, diagnosis, or treatment. Always follow your healthcare provider's advice.

Clairop logs meals, symptoms and stool in seconds, then looks for the foods your gut reacts to, including reactions that land days later.

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