Preclinical stages of Crohn’s disease defined by faecal calprotectin in asymptomatic first-degree relatives

We read with great interest the recent article by Turner et al published in Gut, which evaluated the use of faecal calprotectin to define preclinical stages of Crohn’s disease (CD) in asymptomatic first-degree relatives (FDRs) of patients with CD.1 The study proposes a novel framework for identifying high-risk individuals for prevention trials, based on persistent elevation of faecal calprotectin levels. This work represents an important step towards intercepting CD before symptomatic onset. They found that faecal calprotectin serves as a practical, non-invasive biomarker for detecting subclinical inflammation. Their finding that approximately 19% of asymptomatic FDRs had persistently elevated calprotectin (>70 µg/g on repeated tests) provides a quantifiable metric for risk stratification. Particularly compelling is the derivation of a specific calprotectin threshold (>225 µg/g) that predicted presymptomatic CD with high accuracy, offering a potential tool for clinical decision-making. The study design, which incorporated confirmatory video capsule endoscopy or ileocolonoscopy, adds diagnostic credibility to the calprotectin findings. Furthermore, the sensitivity analysis that accounted for missing data strengthens the validity of their prevalence estimates, suggesting that up to 5.1% of screened FDRs may have presymptomatic CD.