About the Paediatric Ulcerative Colitis Activity Index (PUCAI)
Six clinical items — abdominal pain, rectal bleeding, stool consistency, stool frequency, nocturnal stools and activity level — sum to a total of 0 to 85, with no blood tests and no endoscopy required. Below 10 is remission, 10–34 mild, 35–64 moderate and 65 or above severe, which is the definition of acute severe ulcerative colitis in children. The thresholds that change management most are the serial ones: a PUCAI above 45 on day 3 of intravenous steroids identifies likely non-responders, and above 70 on day 5 is the trigger to start second-line therapy.
Formula
PUCAI = abdominal pain + rectal bleeding + stool consistency + stool frequency + nocturnal stools + activity level
Maximum: 10 + 30 + 10 + 15 + 10 + 10 = 85- abdominal pain
- 0 none · 5 can be ignored · 10 cannot be ignored.
- rectal bleeding
- 0 none · 10 small amount in under 50% of stools · 20 small amount with most stools · 30 large amount, over 50% of stool content.
- stool consistency
- 0 formed · 5 partially formed · 10 completely unformed. Judged on most stools.
- stool frequency
- 0 for 0–2 per 24 h · 5 for 3–5 · 10 for 6–8 · 15 for more than 8.
- nocturnal stools
- 0 none · 10 any episode causing wakening.
- activity level
- 0 no limitation · 5 occasional limitation · 10 severe restricted activity.
- Every item is a multiple of 5, so every possible total is a multiple of 5. The band edges at 10, 35 and 65 are therefore exact rather than approximate, and a score of 34 or 64 cannot occur.
- Rectal bleeding carries 30 of the 85 available points — more than a third of the index — so grading it carelessly moves the result more than any other item.
- The index is entirely clinical. Adding laboratory items and an endoscopic appearance item did not improve its performance in the derivation study, which is why none are included.
- Stool frequency is per 24 hours, and stool consistency refers to most stools rather than the worst single stool.
- The score assesses the previous 24 hours, which is what makes daily use during an acute admission meaningful.
Interpreting the result
Below 10 is clinical remission and is the treatment target; 10–34 is mild, 35–64 moderate, and 65 or above defines acute severe ulcerative colitis. The severe band is not simply a description — a PUCAI of 65 or above is an indication for admission and intravenous corticosteroids. From that point the serial values do the work. A PUCAI above 45 on day 3 identifies a child unlikely to respond to steroids alone, and is the point at which second-line therapy is prepared and the surgical team is brought into the conversation rather than called later. A PUCAI above 70 on day 5 is the threshold for actually starting second-line therapy, whether infliximab or a calcineurin inhibitor. Those two numbers are the reason the index is calculated daily on the ward rather than once on admission.
| Score | Band | What it means | Action |
|---|---|---|---|
| < 10 | Remission | Clinical remission, and the treatment target in the ECCO/ESPGHAN guideline. In practice means a score of 0 or 5 | Maintain current therapy; consider faecal calprotectin, since clinical remission can coexist with mucosal inflammation |
| 10–34 | Mild activity | Mild disease activity, short of the remission target | Optimise 5-ASA and reassess; the target is a score below 10, not merely a lower one |
| 35–64 | Moderate activity | Moderate disease activity | Consider escalation beyond 5-ASA; review in days rather than weeks |
| ≥ 65 | Severe activity | Defines acute severe ulcerative colitis; an admission-level result rather than a clinic one | Admit for intravenous corticosteroids, then recalculate on day 3 (>45 predicts non-response) and day 5 (>70 triggers second-line therapy) |
What the PUCAI needs (6 inputs)
- Abdominal pain
- No pain 0; pain can be ignored 5; pain cannot be ignored 10.
- Rectal bleeding
- None 0; small amount in under 50% of stools 10; small amount with most stools 20; large amount, over 50% of stool content 30. The heaviest-weighted item in the index.
- Stool consistency of most stools
- Formed 0; partially formed 5; completely unformed 10.
- Number of stools per 24 hours
- 0–2 scores 0; 3–5 scores 5; 6–8 scores 10; more than 8 scores 15.
- Nocturnal stools
- Any episode causing wakening scores 10; none scores 0. A binary item worth asking about explicitly, since children and parents often do not volunteer it.
- Activity level
- No limitation 0; occasional limitation 5; severe restricted activity 10. This is the item that captures how much the illness is actually costing the child.
What it returns
- PUCAI total
- 0 to 85, and always a multiple of 5 because every item is. Higher means more active disease.
- Activity band
- Remission (under 10), mild (10–34), moderate (35–64) or severe (65+).
- Item breakdown
- Each item's contribution, which matters because a single item can move the band — rectal bleeding alone can carry a child from remission to moderate.
How it is calculated
The index was built rather than adapted. Turner's group ran a Delphi process with 36 experts to generate candidate items, then narrowed them by regression modelling in 157 patients, testing clinical items alongside laboratory values and an endoscopic appearance item. Six clinical items survived as significant predictors, and — the finding that shaped the final instrument — neither the laboratory items nor the endoscopic item improved performance once those six were included. That is why a validated activity index for a disease defined by mucosal inflammation contains no blood test and no scope. The resulting index was validated in a separate cohort of 48 children undergoing colonoscopy and its responsiveness assessed in 75 children at follow-up. The point weights are not arbitrary: rectal bleeding earned 30 of the 85 available points because it carried the most discriminatory information, which is also why it is the item most worth grading carefully.
Facts & figures
| Item | Options and points | Maximum |
|---|---|---|
| Abdominal pain | None 0 · can be ignored 5 · cannot be ignored 10 | 10 |
| Rectal bleeding | None 0 · small, under 50% of stools 10 · small with most stools 20 · large, over 50% 30 | 30 |
| Stool consistency | Formed 0 · partially formed 5 · completely unformed 10 | 10 |
| Stools per 24 h | 0–2 → 0 · 3–5 → 5 · 6–8 → 10 · over 8 → 15 | 15 |
| Nocturnal stools | No 0 · yes 10 | 10 |
| Activity level | No limitation 0 · occasional 5 · severe restriction 10 | 10 |
Total 0–85. Rectal bleeding alone accounts for more than a third of the available points.
| Timing | PUCAI | What it means |
|---|---|---|
| Admission | ≥ 65 | Defines acute severe ulcerative colitis — admit for intravenous corticosteroids |
| Day 3 | > 45 | Unlikely to respond to steroids alone — prepare second-line therapy and involve the surgical team |
| Day 5 | > 70 | Start second-line therapy (infliximab or a calcineurin inhibitor) rather than continue steroids alone |
| Day 5 | ≤ 70 | Continue steroids and reassess; many in this group still respond |
These serial cut-offs are why the index is recalculated daily during an admission. They come from the prospective severe-colitis cohort and are carried into the ECCO/ESPGHAN acute severe colitis guideline.
Evidence
Derivation and validation — Turner et al.
2007 · n = 157Items were generated by a Delphi process involving 36 experts, then refined by regression modelling in 157 patients. Six clinical items were significant; laboratory items and an endoscopic appearance item did not improve performance. Validation was carried out in a separate cohort of 48 children undergoing colonoscopy, with responsiveness assessed in 75 children at follow-up.
Highly correlated with physician global assessment (r = 0.91), the Mayo score (r = 0.95) and colonoscopic appearance (r = 0.77). Interobserver and test-retest reliability were excellent (intraclass correlation coefficient 0.95, 95% CI 0.93–0.97). Responsiveness to change gave an effect size of 1.9 with an area under the ROC curve of 0.97.
Acute severe colitis thresholds — Turner et al.
2010Prospective multicentre study of children admitted with severe ulcerative colitis treated with intravenous corticosteroids, examining outcomes and predictors of response.
Established the serial PUCAI thresholds now in routine use: a day-3 score above 45 predicts failure of corticosteroids alone, and a day-5 score above 70 identifies children who should be started on second-line therapy.
ECCO/ESPGHAN guideline adoption
2018Joint evidence-based guidelines of the European Crohn's and Colitis Organisation and the European Society for Paediatric Gastroenterology, Hepatology and Nutrition, covering ambulatory care and acute severe colitis in children.
Adopt the PUCAI as the standard activity measure in paediatric ulcerative colitis, with a score below 10 as the definition of remission and the day-3 and day-5 thresholds structuring the management of acute severe colitis.
How it compares
PUCAI vs Mayo score
PUCAI is the right instrument in children — it is non-invasive, validated in paediatric patients, and correlates with the Mayo score at r = 0.95.
The Mayo score includes an endoscopic subscore, which in a child means a general anaesthetic and makes frequent reassessment impractical. The PUCAI was built to track the same construct without that requirement, and the correlation between them is high enough that little is lost. The partial Mayo score drops the endoscopy but was still derived and validated in adults.
PUCAI vs Truelove and Witts criteria
Use PUCAI in children — Truelove and Witts was derived in adults in 1955 and its thresholds do not transfer to paediatric physiology.
Truelove and Witts defines severe colitis by six or more bloody stools daily plus systemic features including pulse above 90 and temperature above 37.8 °C. Those vital-sign thresholds are meaningless in a small child, whose normal heart rate already exceeds 90. The PUCAI's severe threshold of 65 serves the same purpose in paediatrics and is what the ECCO/ESPGHAN guideline uses.
PUCAI vs Simple Clinical Colitis Activity Index (SCCAI)
SCCAI is the adult counterpart — same idea, non-invasive clinical scoring, but derived and validated in adults.
Both indices avoid endoscopy and rely on stool frequency, bleeding, urgency and general wellbeing, and both were built for repeated use. They are not interchangeable: the item sets, weights and thresholds differ, and only the PUCAI has the validated day-3 and day-5 thresholds for paediatric acute severe colitis.
PUCAI vs UCEIS
Complementary — UCEIS scores what the mucosa looks like, PUCAI scores how the child is, and a child can be in clinical remission with active mucosal disease.
UCEIS grades vascular pattern, bleeding and erosions or ulcers at endoscopy, so it answers the mucosal healing question the PUCAI cannot. In paediatric practice the two are used at different tempos: PUCAI at every contact and during an admission, UCEIS at the relatively infrequent endoscopies.
Pearls & pitfalls
- Every item is a multiple of 5, so the total always is too. A PUCAI of 34 or 64 is arithmetically impossible, and a score that is not a multiple of 5 means an item was mis-entered.
- Rectal bleeding carries 30 of the 85 points. Distinguishing 'small amount with most stools' (20) from 'large amount, over 50% of stool content' (30) changes the band on its own in a borderline case.
- Ask about nocturnal stools explicitly. Families rarely volunteer it, and it is a binary 10-point item.
- A PUCAI of 65 or above is not simply 'severe' — it is the definition of acute severe ulcerative colitis and an indication for admission and intravenous corticosteroids.
- The day-3 and day-5 thresholds are different numbers (45 and 70) and mean different things: day 3 says prepare second-line therapy, day 5 says start it. Confusing them delays rescue treatment.
- It is a clinical index. A child can sit in clinical remission with persisting mucosal inflammation, so a PUCAI below 10 is not evidence of mucosal healing.
- Exclude Clostridioides difficile and cytomegalovirus in a severe flare. The index measures activity and cannot distinguish a disease flare from an infection driving one.
- The index applies to ulcerative colitis, not Crohn's disease, and was validated in children rather than adults.
Critical actions
- Admit any child with a PUCAI of 65 or above for intravenous corticosteroids and daily reassessment.
- Recalculate on day 3. A score above 45 is the trigger to prepare second-line therapy and to bring the surgical team into the discussion before it becomes urgent.
- Recalculate on day 5. A score above 70 is the point at which second-line therapy is started rather than prepared.
- Screen for Clostridioides difficile and cytomegalovirus at the start of any severe flare.
- Treat to a target of remission — a PUCAI below 10 — rather than to symptomatic improvement alone.
- Pair the index with faecal calprotectin over time, since clinical remission and mucosal healing do not always coincide.
Why this score exists
The most informative thing about the PUCAI is what its authors left out. They tested laboratory items and an endoscopic appearance item alongside the clinical ones, and found that neither improved the index once the six clinical items were in it. For a disease defined by mucosal inflammation, arriving at a validated activity measure containing no blood test and no scope is a genuinely surprising result, and it is what makes the index usable in children — where every endoscopy means a general anaesthetic and every blood test is a negotiation. The weighting reflects the same empirical approach: rectal bleeding carries 30 of 85 points not because it is the most distressing symptom but because it carried the most information in the regression.
About the creator
First author, 2007 derivation and validation study
Led the development of the PUCAI and the subsequent severe-colitis work that produced the day-3 and day-5 thresholds.
Co-author of the 2007 derivation and validation study.
Co-author of the 2007 derivation and validation study.
Limitations
- Entirely clinical, so it cannot assess mucosal healing. A child in clinical remission by PUCAI may still have significant endoscopic inflammation.
- Symptom-based items depend on history from a child and their family, which introduces recall and reporting variability that a laboratory value would not have.
- The heavy weighting of rectal bleeding means an infective or fissure-related bleed can inflate the score independently of colitis activity.
- Validated in ulcerative colitis and in children; it does not apply to Crohn's colitis or to adults.
- Cannot distinguish a disease flare from a superimposed infection such as Clostridioides difficile or cytomegalovirus, both of which need excluding separately.
- The multiple-of-5 granularity means the index cannot register small changes — the smallest possible change in the score is 5 points.
- Does not account for extraintestinal manifestations, growth failure or nutritional status, all of which matter in paediatric disease and none of which appear in the index.
If you are the patient
The PUCAI is a score doctors use to measure how active a child's ulcerative colitis is, using only questions — no blood tests and no camera test. It asks about six things over the last day: tummy pain, blood in the stool, how loose the stools are, how many there were, whether any woke the child at night, and how much the illness limited normal activity. Each answer scores points, and they add up to somewhere between 0 and 85. Under 10 means the disease is in remission, which is the goal of treatment. Sixty-five or above means a severe flare, and usually means coming into hospital for steroids given through a drip. If that happens, the team will work the score out again every day, because two particular days matter: the score on day 3 tells them whether the steroids are likely to be enough, and the score on day 5 tells them whether to switch to a different treatment. Being able to track all this without repeated camera tests is exactly why the score was designed this way — a colonoscopy in a child needs a general anaesthetic.
Frequently asked questions
What is the PUCAI?#
The Paediatric Ulcerative Colitis Activity Index: six clinical items — abdominal pain, rectal bleeding, stool consistency, stool frequency, nocturnal stools and activity level — summed to a total of 0 to 85. It requires no blood tests and no endoscopy.
What PUCAI score is remission?#
Below 10. Because every item scores a multiple of 5, that means a total of 0 or 5 in practice. Remission by this definition is the treatment target in the ECCO/ESPGHAN guideline.
What are the PUCAI severity bands?#
Below 10 is remission, 10–34 mild, 35–64 moderate, and 65 or above severe. A score of 65 or above is the definition of acute severe ulcerative colitis in children.
What are the day-3 and day-5 PUCAI thresholds?#
During an admission for acute severe colitis on intravenous steroids, a PUCAI above 45 on day 3 identifies a child unlikely to respond to steroids alone and is the point to prepare second-line therapy and involve surgery in the discussion. A PUCAI above 70 on day 5 is the threshold to start second-line therapy such as infliximab or a calcineurin inhibitor.
Why does the PUCAI include no blood tests?#
Because they did not help. The derivation study tested laboratory items and an endoscopic appearance item alongside the clinical ones, and neither improved the index's performance once the six clinical items were included.
Can a PUCAI score be 32 or 47?#
No. Every item scores a multiple of 5, so every possible total is a multiple of 5. A score that is not a multiple of 5 means an item has been entered incorrectly.
Does a PUCAI below 10 mean the bowel has healed?#
No. The PUCAI measures clinical activity only, and a child can be in clinical remission with persisting mucosal inflammation. Faecal calprotectin or endoscopy is needed to assess mucosal healing.
Can the PUCAI be used in adults or in Crohn's disease?#
No. It was derived and validated in children with ulcerative colitis. SCCAI or the Mayo score are the adult ulcerative colitis equivalents, and Crohn's disease has its own indices such as the CDAI and Harvey-Bradshaw.
References
Original / primary reference
Acute severe colitis thresholds
Guidelines
- Turner D, Ruemmele FM, Orlanski-Meyer E, et al. Management of Paediatric Ulcerative Colitis, Part 1: Ambulatory Care — An Evidence-based Guideline From ECCO and ESPGHAN. J Pediatr Gastroenterol Nutr. 2018;67(2):257-291.
- Turner D, Ruemmele FM, Orlanski-Meyer E, et al. Management of Paediatric Ulcerative Colitis, Part 2: Acute Severe Colitis — An Evidence-based Consensus Guideline From ECCO and ESPGHAN. J Pediatr Gastroenterol Nutr. 2018;67(2):292-310.