Clinical decision support

Practice guidelines and risk calculators

Third-party guidelines and prediction tools relevant to IBD-unclassified, each independently verified against PubMed. These are external documents and tools, linked, not reproduced, and not evidence-gated by this site.

Practice guidelines

• ECCO-ESGAR-ESP-IBUS Guideline on Diagnostics and Monitoring of Patients with Inflammatory Bowel Disease: Part 1 ECCO / ESGAR / ESP / IBUS · 2025 · PMID 40741688 · J Crohns Colitis
  What diagnostic work-up is required before a colitis can be labelled IBD-unclassified, and what further testing (ileocolonoscopy with segmental biopsies, small-bowel imaging, capsule endoscopy) may reclassify it as CD or UC.
• ECCO-ESGAR-ESP-IBUS Guideline on Diagnostics and Monitoring of Patients with Inflammatory Bowel Disease: Part 2 ECCO / ESGAR / ESP / IBUS · 2025 · PMID 40742985 · J Crohns Colitis
  How to monitor an established IBD diagnosis over time, including post-operative assessment and cancer surveillance, the setting in which an IBDu label is most often revised.
• ECCO Topical Review on Pouch Disorders ECCO · 2025 · PMID 40574702 · J Crohns Colitis
  Diagnosis and management of inflammatory, functional, structural and neoplastic J-pouch disorders. The reference for what to expect and how to treat when an IBDu patient has an IPAA. Holubar is a co-author.
• AGA Clinical Practice Guideline on the Management of Pouchitis and Inflammatory Pouch Disorders AGA · 2024 · PMID 38128971 · Gastroenterology
  GRADE-based treatment of pouchitis, Crohn's-like disease of the pouch and cuffitis, 9 recommendations, all conditional. The only fully GRADE-graded pouch guideline.
• Diagnosis and classification of ileal pouch disorders: consensus guidelines from the International Ileal Pouch Consortium International Ileal Pouch Consortium · 2021 · PMID 34416186 · Lancet Gastroenterol Hepatol
  The canonical taxonomy of pouch disorders (structural, inflammatory, functional, neoplastic) used to define endpoints in pouch-outcome studies, including IBDu cohorts.
• Treatment of pouchitis, Crohn's disease, cuffitis, and other inflammatory disorders of the pouch: consensus guidelines from the International Ileal Pouch Consortium International Ileal Pouch Consortium · 2022 · PMID 34774224 · Lancet Gastroenterol Hepatol
  Treatment companion to the classification document above, how to escalate therapy for chronic pouchitis and Crohn's disease of the pouch, the commonest reason an IBDu pouch is re-labelled as CD.
• Clinical Practice Guideline for the Surgical Management of Ulcerative Colitis ASCRS · 2026 · PMID 42165399 · Dis Colon Rectum
  Current ASCRS surgical guideline: staging of colectomy/IPAA, emergency indications, and management of dysplasia/cancer. Table 3 lists what changed vs the 2021 edition. Dis Colon Rectum 2026;69:2012-2039.
• ACG Clinical Guideline Update: Ulcerative Colitis in Adults ACG · 2025 · PMID 40701556 · Am J Gastroenterol
  Current US medical-management guideline for UC, including thresholds for referral to colectomy. Supersedes the widely-cited 2019 Rubin guideline.
• British Society of Gastroenterology guidelines on inflammatory bowel disease in adults: 2025 BSG · 2025 · PMID 40550582 · Gut
  Comprehensive UK guideline covering diagnosis and management of both CD and UC, useful where an IBDu patient must be treated as one or the other. Supersedes the 2019 Lamb guideline.
• ESPGHAN revised Porto criteria for the diagnosis of inflammatory bowel disease in children and adolescents ESPGHAN (Paediatric IBD Porto Group) · 2014 · PMID 24231644 · J Pediatr Gastroenterol Nutr
  The only guideline that sets out explicit positive diagnostic criteria for IBD-unclassified (rather than defining it as a diagnosis of exclusion), and separates typical from atypical UC. Still the reference standard for IBDu classification at any age.
• Management of paediatric ulcerative colitis, part 1: Ambulatory care, An updated evidence-based consensus guideline from ESPGHAN and ECCO ESPGHAN / ECCO · 2025 · PMID 40677018 · J Pediatr Gastroenterol Nutr
  Updates the 2018 paediatric UC guideline and contains dedicated sections on IBD-unclassified and on pouchitis; 39 recommendations plus 77 practice points. Open access.

Risk calculators and prediction tools

• Pouchitis Disease Activity Index (PDAI) formula only, no calculatornot validated18-point composite of clinical symptoms, endoscopic appearance and acute histologic inflammation; score ≥7 defines pouchitis. The instrument that operationally defines the commonest pouch outcome measured in IBDu series. · PMID 8170189 Note: NOT a validated instrument. Derived in 1994 on 25 patients total (10 with pouchitis, 15 controls). A 2022 systematic review of 21 operating-property studies (PMID 34180986) concluded no pouchitis index is fully valid, reliable or responsive; PDAI inter-rater reliability was only fair-to-moderate (kappa 0.44) and clinical subscores correlate poorly with endoscopic/histologic subscores. A separate study found antibiotics benefit many symptomatic patients scoring <7, so the diagnostic threshold misses treatment-responders. There is no official web calculator. No MDCalc entry exists; it must be scored by hand from the published table, and it requires biopsy histology, so it is not a bedside tool.
• Modified Pouchitis Disease Activity Index (mPDAI) formula only, no calculatornot validatedPDAI with the histology subscore dropped (clinical + endoscopic only); score ≥5 defines pouchitis. The practical version usable at the time of pouchoscopy without waiting for pathology. · PMID 12794576 Note: Shares the PDAI's validation problem and is arguably weaker: inter-rater reliability kappa 0.389, i.e. lower than the parent index. Derived by excluding patients with chronic refractory pouchitis AND patients with Crohn's disease. Precisely the populations an IBDu pouch is most likely to become, so its performance in IBDu is untested. Reported sensitivity/specificity are against the unvalidated PDAI as reference standard, not against an independent gold standard.

Also on MDCalc

These are established instruments already hosted as free, working calculators by MDCalc. We link them rather than rebuild them. Our own decision-support tools above cover what MDCalc does not, and every link below was verified against MDCalc directly.

• Montreal Classification for IBD live calculatorclassificationAssigns Montreal extent (E1-E3) and severity (S0-S3) for UC, and age / location / behaviour (A, L, B) for Crohn's. Note: A PHENOTYPE classification, not a prediction model. Extent should be recorded as the maximum ever documented, not the most recent endoscopic appearance, which underestimates true extent in quiescent disease.
• Truelove and Witts Severity Index for Ulcerative Colitis live calculatorclassificationClassifies a UC flare as mild / moderate / severe. The 'severe' band is the operational definition of acute severe UC (ASUC). Note: A 1955 classification, not a prediction model, never validated to predict steroid failure or colectomy. Deliberately sensitive rather than specific: only ONE systemic criterion beyond the stool count is needed.
• Mayo Score / Disease Activity Index (DAI) for Ulcerative Colitis live calculatoractivity indexThe standard UC trial activity index: stool frequency, rectal bleeding, endoscopy subscore and physician global assessment. Note: An ACTIVITY index, not a risk model. The endoscopic subscore requires a scope, so the 'partial Mayo' seen in clinic is a different instrument with different thresholds, say which one you mean.
• Ulcerative Colitis Endoscopic Index of Severity (UCEIS) live calculatorendoscopicScores endoscopic severity from vascular pattern, bleeding and erosions/ulcers. Note: NOTE the published scoring was CORRECTED: BSG 2019's table 3 printed the original scale where normal = 1 (range 3-11); the corrected scale is normal = 0 (range 0-8). Confirm which scale a given source is using before comparing scores.
• Crohn's Disease Activity Index (CDAI) live calculatoractivity indexThe historical primary endpoint in Crohn's trials; requires a 7-day patient diary plus labs. Note: Correlates POORLY with endoscopic inflammation. A normal CDAI does not exclude active disease. Explicitly invalid in stricturing/fistulising disease, after extensive resection, and in patients with a stoma. Pair with CRP/faecal calprotectin and imaging.
• Harvey-Bradshaw Index (HBI) for Crohn's Disease live calculatoractivity indexThe single-day simplified CDAI used in clinic; remission conventionally <5. Note: Symptom-driven, so it shares CDAI's blindness to endoscopic activity. The severity bands are from the literature, not from MDCalc's page.

Guideline summaries hosted by MDCalc:

• ACG: Preventive Care in Inflammatory Bowel Disease (via MDCalc) guidelineVaccination, bone health, skin-cancer and cervical-screening recommendations for immunosuppressed IBD patients. Note: Directly relevant before starting biologics or immunomodulators, and a frequent gap in surgical clinics.
• AGA: Pharmacological Management of Ulcerative Colitis (via MDCalc) guidelineAGA medical-therapy recommendations for UC. Note: Medical therapy only. It does not address surgical indications or timing.