Synopsis
Use reproducible clinical scores, biomarkers, endoscopy and cross-sectional imaging to distinguish symptoms from inflammation and make treatment changes against explicit, patient-relevant targets.
- IBD diagnosis is synthetic: symptoms, stool testing, endoscopy, histology and imaging establish chronic inflammation and distribution while excluding infection and alternative pathology.
- A clinical activity score standardises communication but is not a substitute for judgement; many scores include symptoms that anaemia, infection, bile-acid diarrhoea or irritable bowel physiology can reproduce.
- Use the same validated score longitudinally for the same question: Truelove and Witts for ASUC, partial Mayo or SCCAI for UC, and Harvey-Bradshaw or another agreed index for Crohn disease.
- Faecal calprotectin is a non-specific marker of intestinal neutrophilic activity whose trend is most useful when linked to the individual's phenotype, previous values and local assay.
- CRP is convenient but can remain normal in active disease; albumin, blood count and weight add severity and nutritional context rather than replacing direct bowel assessment.
- Endoscopy assesses mucosal healing and dysplasia; MR enterography or intestinal ultrasound assesses transmural small-bowel disease, strictures and fistulae; neither modality answers every target.
- Treat-to-target means agreeing short-term symptom and biomarker goals plus longer-term objective control, then acting when they are missed instead of waiting for irreversible damage.
- Therapeutic drug monitoring can explain non-response to selected biologics, but levels and antibodies must be interpreted with timing, inflammation, adherence and the clinical decision.
Key red flags
A severity score never overrules shock, peritonism, obstruction, major haemorrhage, toxic dilatation or sepsis; stabilise and image urgently.
Rapid clinical deterioration with a previously low calprotectin may reflect perforation, abscess, thrombosis or non-inflammatory illness and needs direct assessment.
Capsule endoscopy is unsafe when a stricture or obstruction has not been excluded.
Do not delay treatment of acute severe colitis while awaiting an elective full colonoscopy or a send-away drug level.
Unexpected high-grade dysplasia, invisible dysplasia or a stricture needs expert pathology, endoscopy and colorectal MDT review rather than routine surveillance recall.
Investigation priorities
Support diagnosis and track neutrophil-driven luminal inflammation non-invasively.
Management branches
New IBD is suspected or a transferred patient lacks a clear phenotype and objective baseline.
- Record symptoms using an agreed clinical index, but separately document weight, function, steroid exposure, perianal and extra-intestinal disease.
- Obtain infection tests, calprotectin, CRP, blood count, albumin, renal, liver, iron and phenotype-specific nutrition markers.
- Use ileocolonoscopy with mapped biopsies plus small-bowel imaging for Crohn suspicion, adding pelvic MRI, upper endoscopy or capsule only when the question requires it.
- Store extent, behaviour, validated endoscopic activity, histology, complications and patient priorities as the comparator for later treat-to-target review.