About the Simple Clinical Colitis Activity Index (SCCAI)
The SCCAI measures ulcerative colitis activity from symptoms alone, with no endoscopy or blood test: five patient-reportable items — daytime stool frequency, night-time stool frequency, urgency of defecation, blood in the stool, and general wellbeing — plus a count of extracolonic features, added to a single total. A score of 2 or below is remission, and a score of 5 or more has been validated as defining a relapse, with 92% sensitivity and 93% specificity against a clinician's global assessment. Because it needs nothing beyond the patient's own report, it can be completed in clinic, over the phone, or by the patient at home.
Formula
SCCAI = daytime frequency + night-time frequency + urgency + blood + general wellbeing + extracolonic manifestations (count)- daytime frequency
- 0–3.
- night-time frequency
- 0–2.
- urgency
- 0–3.
- blood
- 0–3.
- general wellbeing
- 0–4.
- extracolonic manifestations
- One point each: arthritis, pyoderma gangrenosum, erythema nodosum, uveitis.
- The five core symptom items are equally weighted and sum to a maximum of 15; extracolonic manifestations add a small further count.
- Every item is patient-reportable, which is what makes self-administration possible — the score correlates closely whether completed by patient or clinician.
- Remission is conventionally a total of 2 or below; a score of 5 or more has been validated as a threshold for relapse.
Interpreting the result
A total of 2 or below is clinical remission and supports continuing maintenance therapy, ideally with endoscopic or biomarker confirmation rather than symptoms alone. Rising scores indicate increasing activity, and the most useful validated cut-off is relapse: a score of 5 or more identified relapse with 92% sensitivity and 93% specificity against a clinician's global judgement. This means the boundary between the 'mild' and 'moderate-to-severe' bands is not arbitrary — it sits where a validated relapse threshold has been drawn, so a patient crossing from a score of 5 into 6 or above should generally be treated as relapsing and worked up accordingly. Because symptoms and inflammation diverge in ulcerative colitis, a high SCCAI should still be corroborated with faecal calprotectin or CRP before therapy is escalated.
| Score | Band | What it means | Action |
|---|---|---|---|
| ≤ 2 | Remission | Clinical remission by the conventional cut-off | Continue maintenance therapy; confirm with calprotectin or endoscopy where escalation is considered |
| 3–5 | Mildly active | Mild clinical activity — a score of 5 sits at the validated relapse threshold | Check calprotectin or CRP; optimise therapy and reassess |
| > 5 | Moderately to severely active | A score above 5 is generally taken as a relapse | Confirm inflammation, exclude infection including C. difficile, and escalate therapy |
What the SCCAI needs (6 inputs)
- Bowel frequency — daytime
- 1–3 (0), 4–6 (1), 7–9 (2), or more than 9 (3) stools per day.
- Bowel frequency — night
- None (0), 1–3 (1), or 4–6 (2). Nocturnal stools point to genuinely active disease rather than functional symptoms.
- Urgency of defecation
- None (0), hurry (1), immediately (2), or incontinence (3).
- Blood in stool
- None (0), trace (1), occasionally frank (2), or usually frank (3).
- General wellbeing
- Very well (0), slightly below par (1), poor (2), very poor (3), or terrible (4).
- Extracolonic manifestations
- One point each for arthritis, pyoderma gangrenosum, erythema nodosum, and uveitis — enter the number present.
What it returns
- SCCAI total
- The sum of all items. The five symptom items span 0–15, plus any extracolonic points.
- Activity band
- Remission, mildly active, or moderately-to-severely active.
How it is calculated
Walmsley and colleagues derived the index by testing which clinical features tracked disease activity as measured by the more elaborate Powell-Tuck index, which itself blends symptoms, physical signs and sigmoidoscopic appearance. Five symptom items — the two stool-frequency measures, urgency, blood, and wellbeing — reproduced the Powell-Tuck assessment almost exactly (a correlation of 0.959), so the endoscopic and physical-sign components could be dropped without much loss. The resulting score is a plain equally weighted sum: no coefficients, no laboratory values, and nothing that cannot be obtained by asking the patient, which is precisely why it can be self-administered.
Facts & figures
| Score | Meaning | Source |
|---|---|---|
| ≤ 2 | Clinical remission | Conventional cut-off |
| ≥ 5 | Relapse (92% sensitivity, 93% specificity) | Jowett 2003 |
The relapse threshold was validated against a clinician's global assessment of disease status, with 88% positive and 95% negative predictive value.
Evidence
Derivation — Walmsley
1998 · n = 63The candidate items were first assessed in 63 evaluations of ulcerative colitis activity scored against the Powell-Tuck index (which includes symptoms, physical signs and sigmoidoscopic appearance), then the resulting five-item index was evaluated in a further 113 assessments in a different group of patients against a complex clinical-and-laboratory index.
The Simple Clinical Colitis Activity Index correlated with the Powell-Tuck index at 0.959, showing that five patient-reportable symptom items reproduced a much more elaborate assessment closely enough to replace it for initial evaluation of a flare.
Relapse threshold and self-administration — Jowett
2003 · n = 7171 presentations of patients with ulcerative colitis routinely attending hospital, who completed the SCCAI themselves before it was scored independently by a clinician blinded to the patient's answers, with disease status set by the clinician's global assessment.
A score of 5 or more defined relapse with 92% sensitivity, 93% specificity, 88% positive and 95% negative predictive value. Patient and clinician scores differed by only 0.35 on average, confirming the index can be reliably self-administered.
Endoscopy adds little — Higgins
2005 · n = 6666 consecutive ulcerative colitis patients assessed with both invasive indices (St Mark's index, UCDAI) and noninvasive ones (SCCAI, Seo), comparing how well the symptom-only scores tracked the endoscopy-containing ones.
The SCCAI correlated with the invasive St Mark's index at 0.86, and after adjusting for the noninvasive items the endoscopic component of the UCDAI predicted almost none of the remaining variance — supporting symptom-based assessment of activity in routine care.
Patient-reported version (P-SCCAI) — Bennebroek Evertsz
2013 · n = 149149 ulcerative colitis patients completing a patient version of the index (P-SCCAI) around a clinic visit, compared with the clinician-scored SCCAI, CRP and the Physician's Global Assessment.
Patient and clinician scores correlated at 0.79, with 87% agreement on whether disease was active or in remission (κ = 0.66). Patients tended to report slightly more symptoms, but the P-SCCAI agreed with the clinician index well enough to complement it in care and research.
How it compares
SCCAI vs Mayo score (Disease Activity Index)
The SCCAI needs no endoscopy and is built for repeated, even patient-completed, monitoring; the Mayo score includes an endoscopy subscore and is the more common trial instrument for defining response and remission.
The full Mayo score combines stool frequency, rectal bleeding, an endoscopic subscore and a physician's global assessment, so a complete Mayo score requires a scope. The SCCAI drops the endoscopic component entirely, which studies suggest costs little in tracking clinical activity, and adds items — night-time frequency, urgency, extracolonic features — the Mayo score omits. For everyday monitoring the SCCAI is more practical; for a trial endpoint requiring documented mucosal healing, the Mayo score (or the partial Mayo plus a UCEIS) is the usual choice.
SCCAI vs Truelove and Witts criteria
Use the SCCAI to grade and track activity across the mild-to-moderate range in outpatients, and the Truelove and Witts criteria to make the binary admission decision in an acute severe flare.
The Truelove and Witts criteria are a triage rule built around systemic toxicity, designed to identify the acute severe attack that needs hospital and intravenous steroids; they are insensitive to change across the mild-to-moderate range. The SCCAI is a graded symptom index that measures exactly that range and lends itself to frequent, remote monitoring. They serve different moments in the disease course and are complementary rather than competing.
Pearls & pitfalls
- Remission is 2 or below and relapse is 5 or more — the middle is genuinely intermediate, and a score of exactly 5 sits right on the validated relapse boundary, so treat it as significant rather than borderline-mild.
- Nocturnal stools carry particular weight as a marker of true inflammation rather than functional symptoms; do not overlook the night-time frequency item.
- The extracolonic item counts only arthritis, pyoderma gangrenosum, erythema nodosum and uveitis — one point each — not every possible extraintestinal manifestation.
- The index measures symptoms, so confirm a high score reflects inflammation (calprotectin or CRP) before escalating, and exclude infection including C. difficile in any flare.
- It is validated for self-administration, so a patient-reported score is trustworthy — but patients tend to score marginally higher than clinicians, which is expected and not an error.
Critical actions
- Confirm that symptoms driving a raised SCCAI reflect active inflammation, using faecal calprotectin or CRP, before escalating therapy.
- Exclude infection, including Clostridioides difficile, in anyone presenting with a flare.
- If there is bloody diarrhoea with systemic upset, assess against the Truelove and Witts criteria for acute severe colitis rather than relying on the SCCAI alone.
- Aim to confirm remission objectively (calprotectin or endoscopic healing) rather than accepting a low symptom score as proof of mucosal healing.
- Track the trend across visits — a rising score approaching or crossing 5 is a prompt to act, whether or not any single value looks alarming.
Why this score exists
Walmsley and colleagues set out to simplify, not to invent: the Powell-Tuck index already captured ulcerative colitis activity well, but its physical-sign and sigmoidoscopic components made it awkward for the initial evaluation of a flare. Their contribution was to show that five items a patient can report reproduce that fuller assessment almost exactly, which is why the index carries 'simple' in its name and why it has since been adapted into a formally patient-completed form. The design intent — a score obtainable without a scope, at the bedside or by the patient — is exactly what made it fit remote monitoring long before that became routine.
About the creator
First author, 1998 derivation study
Derived a five-item symptom-only index that reproduced the more elaborate Powell-Tuck assessment closely enough to replace it for initial evaluation.
Senior author
Led the Birmingham IBD unit where the simplified index was developed.
Limitations
- It measures symptoms only, so it can be discordant with mucosal inflammation in either direction and does not replace objective markers or endoscopy for confirming healing.
- The extracolonic item is a limited count of four specific manifestations, not a comprehensive extraintestinal assessment.
- It was validated in adults with established ulcerative colitis; it is not designed for the initial diagnostic distinction between colitis and functional bowel symptoms.
- Symptom scores can be inflated by coexisting irritable-bowel-type symptoms or bile-acid diarrhoea, which do not respond to escalating colitis therapy.
- As with any symptom index, patient-completed scores carry a small systematic tendency to run higher than clinician-scored ones.
If you are the patient
The SCCAI is a simple questionnaire that measures how active your ulcerative colitis is, using only your symptoms — how many times you open your bowels in the day and at night, how urgent it feels, whether there is blood, how well you feel in yourself, and whether you have certain joint, skin or eye problems linked to colitis. It adds up to a single number. A score of 2 or less usually means your colitis is settled (in remission), while a score of 5 or more suggests a flare-up. Because it needs no camera test or blood test, you can fill it in yourself at home or over the phone, and it has been shown to give much the same answer whether you or your doctor scores it. If your score is high, your team will usually also check a stool or blood test to confirm the symptoms are due to inflammation before changing treatment.
Frequently asked questions
What is a normal or remission SCCAI score?#
A total of 2 or below is taken as clinical remission. Scores of 3–5 indicate mild activity, and a score of 5 or more has been validated as defining a relapse.
What SCCAI score means a flare or relapse?#
A score of 5 or more. In the validation study that threshold identified relapse with 92% sensitivity and 93% specificity against a clinician's global assessment of disease status.
Can patients complete the SCCAI themselves?#
Yes. It was specifically shown to be reliable when self-administered — patient and clinician scores differed by only about 0.35 on average — and a formal patient version (the P-SCCAI) agrees well with the clinician-scored index.
Does the SCCAI require endoscopy?#
No. It uses only patient-reportable symptoms and an extracolonic-manifestation count, with no endoscopy or blood tests, which is what distinguishes it from indices such as the full Mayo score.
Does a low SCCAI prove there is no inflammation?#
Not on its own. It measures symptoms, and symptoms can lag behind or run ahead of mucosal inflammation, so objective markers such as faecal calprotectin or endoscopy are used to confirm true healing.
How many items does the SCCAI contain?#
Six: daytime stool frequency, night-time stool frequency, urgency of defecation, blood in the stool, general wellbeing, and extracolonic manifestations. All are symptom-based and none requires a blood test or endoscopy, which is what allows the index to be completed anywhere, including by the patient.
Can the SCCAI be used by telephone or in a remote consultation?#
Yes, and that is one of its practical strengths. Because every item is a symptom the patient can report, the index can be completed by telephone, in a video consultation or through a patient portal, and self-administered SCCAI scores correlate well with clinician-completed ones. That makes it well suited to flare triage and remote monitoring, where the alternative is a subjective account with no comparable number attached.
How does the SCCAI compare with the partial Mayo score?#
Both are symptom-only indices used for the same purpose, and both avoid endoscopy. The SCCAI includes urgency and night-time stool frequency, which patients often identify as the most disabling features and which the partial Mayo omits; the partial Mayo includes a physician global assessment, which the SCCAI does not. Neither is clearly superior, and the practical advice is to pick one and use it consistently, because scores from the two are not interchangeable.
References
Original / primary reference
Validation
- Jowett SL, Welfare MR, Barton JR, et al. Defining relapse of ulcerative colitis using a symptom-based activity index. Scand J Gastroenterol. 2003;38(2):164-171.
- Higgins PDR, Schwartz M, Mapili J, et al. Is endoscopy necessary for the measurement of disease activity in ulcerative colitis? Am J Gastroenterol. 2005;100(2):355-361.
- Bennebroek Evertsz F, Nieuwkerk PT, Stokkers PCF, et al. The patient simple clinical colitis activity index (P-SCCAI) can detect ulcerative colitis (UC) disease activity in remission. J Crohns Colitis. 2013;7(11):890-900.