PCDAI: how the Pediatric Crohn's Disease Activity Index is scored
The PCDAI adds eleven item scores for a child or adolescent with Crohn's disease: symptoms, examination findings, growth and three blood tests. Most items score 0, 5 or 10; hematocrit and ESR score 0, 2.5 or 5. The total runs from 0 to 100.
Not a medical device. Not a diagnosis or dosing recommendation.
What is the PCDAI?
The Pediatric Crohn's Disease Activity Index (PCDAI) was published by Jeffrey Hyams and colleagues in the Journal of Pediatric Gastroenterology and Nutrition in 1991. It was built for children rather than adapted from an adult index, so growth (weight and height) is part of the score.
Magent's calculator adds the eleven item points you assign and returns the total out of 100. The 1991 paper didn't publish cut scores for inactive, mild or moderate disease, and the calculator doesn't apply any.
This page explains the scoring. It doesn't say what a score means for a particular child.
The PCDAI formula
PCDAI = abdominal pain + stools + well-being 0, 5 or 10 each
+ hematocrit + ESR 0, 2.5 or 5 each
+ albumin + weight + height 0, 5 or 10 each
+ abdomen + perirectal + extra-intestinal 0, 5 or 10 each
total 0 to 100 · no activity bandsExact expression the calculator uses:
PCDAI = abdominal_pain + stools + well_being + hematocrit + esr + albumin + weight + height + abdomen + perirectal + extra_intestinal; Hyams 1991 caller-assigned item points; hematocrit and esr 0, 2.5, or 5; remaining items 0, 5, or 10; max 100; no published activity bandsInputs
| Input | Meaning | Accepted range |
|---|---|---|
abdominal_pain | Abdominal pain points | 0, 5 or 10 |
stools | Stools per day points | 0, 5 or 10 |
well_being | Functioning and general well-being points | 0, 5 or 10 |
hematocrit | Hematocrit points, from the paper's age- and sex-specific table | 0, 2.5 or 5 |
esr | Erythrocyte sedimentation rate points | 0, 2.5 or 5 |
albumin | Serum albumin points | 0, 5 or 10 |
weight | Weight points | 0, 5 or 10 |
height | Height points | 0, 5 or 10 |
abdomen | Abdominal examination points | 0, 5 or 10 |
perirectal | Perirectal disease points | 0, 5 or 10 |
extra_intestinal | Extra-intestinal manifestation points | 0, 5 or 10 |
How the scoring works
You assign each item's points; the calculator adds them. The item descriptions:
| Item | 0 | 5 | 10 |
|---|---|---|---|
| Abdominal pain | None | Mild: brief, doesn't interfere with activities | Moderate or severe: daily, longer lasting, affects activities, nocturnal |
| Stools per day | 0–1 liquid, no blood | Up to 2 semi-formed with small blood, or 2–5 liquid | Gross bleeding, or ≥6 liquid, or nocturnal diarrhea |
| Well-being | No limitation of activities, well | Occasional difficulty keeping up age-appropriate activities | Frequent limitation of activities, very poor |
| Albumin | ≥3.5 g/dL | 3.1–3.4 g/dL | ≤3.0 g/dL |
| Weight | Gain, or voluntary stable or loss | Involuntary stable, or loss of 1–9% | Loss of ≥10% |
| Height (first assessment) | <1 channel decrease | ≥1 and <2 channel decrease | ≥2 channel decrease |
| Height (follow-up) | Height velocity ≥ −1 SD | < −1 SD and > −2 SD | ≤ −2 SD |
| Abdomen | No tenderness, no mass | Tenderness, or mass without tenderness | Tenderness, involuntary guarding, definite mass |
| Perirectal | None, or asymptomatic tags | 1–2 indolent fistulas, scant drainage, no tenderness | Active fistula, drainage, tenderness or abscess |
| Extra-intestinal | None | One | Two or more |
ESR uses half-size steps: under 20 mm/h scores 0, 20 to 50 scores 2.5, over 50 scores 5.
Hematocrit also scores 0, 2.5 or 5, but its cutoffs depend on the child's age and sex. That table comes from the 1991 paper and is applied by the person entering the points; the calculator doesn't hold it and doesn't look up hematocrit values.
The extra-intestinal manifestations counted are fever of 38.5 °C or more for 3 days over the past week, arthritis, uveitis, erythema nodosum and pyoderma gangrenosum.
Inputs and output
Every input is a point value, not a raw measurement. The calculator doesn't examine the child or measure anything. A point value outside an item's allowed set is rejected with an error. It returns each item, the total and the maximum of 100. Half points appear in the total when hematocrit or ESR is 2.5.
Worked examples
These use Magent's own expected values for the calculator.
Example 1: every item 0
- 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0 out of 100.
- No activity band is returned.
Example 2: one 10-point item
- Abdominal pain 10, everything else 0.
- Total 10. The same holds for any one of the nine items scored 0, 5 or 10.
Example 3: hematocrit or ESR alone
- Hematocrit 2.5, everything else 0 → 2.5. Hematocrit 5 → 5.
- ESR 2.5 → 2.5. ESR 5 → 5.
Example 4: every item at its maximum
- Nine items at 10 and hematocrit and ESR at 5 each.
- 90 + 5 + 5 = 100, the maximum.
History of the PCDAI
The index comes from Hyams JS, Ferry GD, Mandel FS and colleagues, Development and validation of a pediatric Crohn's disease activity index, Journal of Pediatric Gastroenterology and Nutrition, 1991 (volume 12, issue 4, pages 439–447). The abstract says a group of senior pediatric gastroenterologists first drafted the index at a research forum. It was then tested on clinical and laboratory observations of children and adolescents with Crohn's disease. Two physician-observers assessed each patient independently, also completing a modified Harvey-Bradshaw index and a global assessment of disease activity. Agreement between observers was excellent, and PCDAI scores rose with disease severity.
When it's used
The PCDAI describes disease activity in a child or adolescent with Crohn's disease at a visit. The height item has separate descriptions for the first assessment and for follow-up.
Where it's used
The items come from history, physical examination, growth measurements and three blood tests: hematocrit, ESR and albumin.
Who uses it
The person using the calculator assigns each item's points, including the hematocrit points from the paper's age and sex table. The calculator adds them.
Limits of the calculation
- The calculator doesn't examine the child, measure growth or run labs. Every item point comes from the person entering it.
- The hematocrit cutoffs by age and sex aren't built in. You assign the hematocrit points.
- It returns a total out of 100 with no activity bands, because the 1991 paper didn't publish cut scores.
- It's the pediatric index. It isn't the adult CDAI, the SES-CD endoscopic score or PUCAI.
- This page doesn't say what to do with a score.
Clinical decisions belong to a qualified clinician who knows the patient.
How it differs from related calculators
- CDAI is the adult Crohn's Disease Activity Index, built from eight variables.
- SES-CD scores what is seen at endoscopy.
- PUCAI is the pediatric index for ulcerative colitis, not Crohn's disease.
- Harvey-Bradshaw index is a shorter, symptom-based index; a modified version was compared with the PCDAI in the 1991 paper.
Glossary
- ESR: erythrocyte sedimentation rate, in mm/h.
- Channel decrease: a drop across one or more percentile lines on a growth chart.
- Height velocity SD: how far the rate of growth sits from the average, in standard deviations.
- Perirectal disease: skin tags, fistulas or abscesses around the anus.
- Extra-intestinal manifestations: features outside the gut, such as arthritis or uveitis.
Common mistakes
- Scoring hematocrit or ESR as 10. Their top value is 5.
- Entering raw lab values. Every input is a point value.
- Using the adult CDAI. The PCDAI is a separate index with different items.
- Looking for an activity band. The calculator returns the total alone.
Source
Hyams JS, Ferry GD, Mandel FS, et al. Development and validation of a pediatric Crohn's disease activity index. J Pediatr Gastroenterol Nutr. 1991;12(4):439-447. DOI: 10.1097/00005176-199105000-00005. PMID: 1678008
Frequently asked questions
How is the PCDAI calculated?
Add the points for eleven items. Nine score 0, 5 or 10; hematocrit and ESR score 0, 2.5 or 5.
What is the highest PCDAI score?
100.
Does the PCDAI have activity bands?
The 1991 paper didn't publish cut scores, so the calculator returns the total without a band.
How is the hematocrit item scored?
With a table by age and sex from the 1991 paper. You assign the hematocrit points (0, 2.5 or 5) from that table; the calculator doesn't look them up.
Is the PCDAI the same as the CDAI?
No. The CDAI is an adult index with different items. The PCDAI includes growth.