What the Pediatric Crohn's Disease Activity Index (PCDAI) is
The Pediatric Crohn's Disease Activity Index (PCDAI) is a composite clinical score that summarizes inflammatory burden in pediatric Crohn's disease. It blends caregiver and patient report for the prior week, findings from physical examination focused on growth and the abdomen, selected extra-intestinal manifestations, and recent laboratory measures. Each domain contributes points within fixed ranges; the total score spans 0 to 100. Half-points arise from the hematocrit and ESR subcomponents. The index was introduced to give pediatric gastroenterology a standardized outcome measure that captures both intestinal symptoms and the nutritional and inflammatory consequences that matter uniquely in children.
Who it is for
PCDAI is intended for children and adolescents with Crohn's disease. Clinical tools and trials commonly cite use through about age 19 years. It describes disease activity, not anatomy alone; mucosal healing, strictures, and growth potential may diverge from the numeric total. The score is most informative when collected serially, alongside growth charts, medication adherence, infection screening, and endoscopic or imaging data when those guide decisions.
Time window and data sources
- History and extraintestinal items refer to the past seven days, matching original scoring intent.
- Laboratory values are typically those drawn within roughly the same week as the assessment.
- Weight change is judged against a prior measurement from at least four to six months earlier.
- Height uses growth channel shift or height velocity relative to reference standards as categorized in the instrument.
Domain structure
Eight clinical domains each contribute up to 10 points, except hematocrit and ESR, which each contribute up to 5 points using 0, 2.5, and 5 point tiers. Albumin contributes up to 10 points. The theoretical maximum is 100.
History (past week), each 0, 5, or 10 points
Abdominal pain: none (0); mild, not materially limiting activities (5); moderate or severe, including daily or nocturnal pain or activity limitation (10).
Stools per day: 0 to 1 liquid stools without blood (0); 2 to 5 liquid stools, or up to 2 semi-formed stools with small amounts of blood (5); 6 or more liquid stools, gross blood, or nocturnal diarrhea (10).
General well-being: well, without activity limitation (0); below par with occasional difficulty maintaining age-appropriate activities (5); very poor with frequent limitation (10).
Examination, each 0, 5, or 10 points
Weight versus prior (4 to 6 months): weight gain, voluntary weight stability, or voluntary weight loss (0); involuntary stable weight or roughly 1 to 9 percent involuntary loss (5); involuntary loss of about 10 percent or more (10).
Height (channel or velocity): under one channel decrease, or height velocity at or above about minus one SD (0); one to under two channel decrease, or velocity between about minus one and minus two SD (5); two or more channel decrease, or velocity at or below about minus two SD (10).
Abdomen: no tenderness and no mass (0); tenderness or a soft mass without guarding (5); tenderness with involuntary guarding or a definite mass (10).
Perirectal disease: none or asymptomatic tags (0); one or two indolent fistulae with scant drainage and no tenderness (5); active fistula, drainage, tenderness, or abscess (10).
Extra-intestinal manifestations (past week), 0, 5, or 10 points
Counts features such as fever 38.5 degrees C or higher on three days, arthritis, uveitis, erythema nodosum, and pyoderma gangrenosum. None (0); one qualifying manifestation (5); two or more (10).
Laboratory components
Hematocrit (0, 2.5, or 5 points)
Anemia reflects chronic inflammation, malabsorption, or bleeding. The score compares hematocrit to age- and sex-specific percent thresholds. Values at or above the higher cutoff earn 0 points; values between the intermediate and higher cutoff earn 2.5 points; values below the intermediate cutoff earn 5 points. On this calculator, children under 6 years use the same bands as ages 6 to 10 years, a frequent convention on educational tools.
| Group | Normal or near-normal (0 pts) | Intermediate (2.5 pts) | Low (5 pts) |
|---|---|---|---|
| Female, age 10 years and under | Hct ≥33% | Hct 28% to 32.9% | Hct <28% |
| Female, over 10 years | Hct ≥34% | Hct 29% to 33.9% | Hct <29% |
| Male, age 10 years and under | Hct ≥33% | Hct 28% to 32.9% | Hct <28% |
| Male, 11 to 14 years | Hct ≥35% | Hct 30% to 34.9% | Hct <30% |
| Male, over 14 years | Hct ≥37% | Hct 32% to 36.9% | Hct <32% |
Erythrocyte sedimentation rate (0, 2.5, or 5 points)
ESR under 20 mm/h (0); 20 to 50 mm/h (2.5); over 50 mm/h (5).
Albumin (0, 5, or 10 points)
Enter albumin in grams per liter (g/L), consistent with SI reporting. Examples: 35 g/L or higher (0); above 30 but below 35 g/L (5); 30 g/L or lower (10). If your laboratory reports g/dL, multiply by ten (for example, 3.5 g/dL equals 35 g/L).
Interpreting the total score
Interpretation should always include clinical context, growth status, and treatment goals.
- Under 10: widely summarized as inactive or minimal activity in pediatric Crohn disease practice and trial reporting.
- 10 to 29: mild to moderate activity in many teaching schemas; therapy changes depend on trajectory, complications, and patient priorities.
- 30 or higher: commonly grouped as moderate to severe activity and often prompts closer evaluation of inflammation, nutrition, adherence, infection, and medication optimization.
A commonly cited rule for treatment response is a decrease of 12.5 points or more after an intervention, representing a clinically meaningful improvement in many educational summaries. Individual centers may use different response definitions for trials or quality metrics.
Strengths and limitations
Strengths: pediatric-specific blend of symptoms, growth, extraintestinal features, and inexpensive labs; familiarity across gastroenterology programs; useful for trending during therapy.
Limitations: does not replace ileocolonoscopy or cross-sectional imaging when mucosal or transmural complications drive decisions; subjective domains can vary by reporter; acute infection or medication effects may shift labs independently of Crohn inflammation; very young children may have less reliable history elements.
Educational use
This description supports learning and documentation practices. It does not establish a standard of care, substitute for specialist judgment, or replace shared decision-making with patients and families.