Preclinical stages of Crohn's disease defined by faecal calprotectin in asymptomatic first-degree relatives: screening framework for prevention trials.

Persistent elevation of faecal calprotectin >70 µg/g in asymptomatic first-degree relatives predicts presymptomatic Crohn's disease with 89% sensitivity and 94% specificity.

• Why it matters: Identifying individuals at high risk for Crohn's disease before symptoms develop is crucial for prevention efforts, but the optimal preclinical detection method remains unclear.
• What they did: Measuring faecal calprotectin in 950 asymptomatic first-degree relatives aged 6-38 years, with follow-up endoscopy for those with persistent elevation, and analyzing calprotectin's predictive value.
• The result: Approximately 19% had persistently elevated calprotectin, and levels >225 µg/g strongly predicted presymptomatic Crohn's disease, supporting calprotectin's role in early risk stratification for prevention trials.