Faecal Calprotectin Testing Supports Primary Care IBD Triage

FAECAL calprotectin testing increased in UK primary care between 2015 and 2023, supporting its role in identifying patients with suspected inflammatory bowel disease (IBD), although differences in testing rates and subsequent referrals highlighted opportunities to improve diagnostic pathways.

A retrospective cohort study examined how faecal calprotectin (FC) testing was used in primary care in England, alongside patient characteristics, referral patterns and subsequent diagnoses. The findings demonstrated the potential of FC testing to support clinical decision-making when assessing patients presenting with lower gastrointestinal (GI) symptoms.

Faecal Calprotectin Testing Increased Over Time

Researchers analysed primary care data from 830,936 adults aged 18–60 years who presented with lower GI symptoms between 2015 and 2023. Overall, 34,944 patients (4.2%) underwent FC testing within the specified assessment period.

Testing increased significantly throughout the study period, rising from 1.6% of symptomatic patients in 2015 to 7.7% in 2023 (p=0.001).

However, several patient characteristics were associated with lower testing rates. Female sex (adjusted odds ratio [aOR]: 0.80; 95% confidence interval [CI]: 0.78–0.82), lower socioeconomic status (aOR: 0.90; 95% CI: 0.86–0.95), smoking (aOR: 0.86; 95% CI: 0.83–0.89), and obesity (aOR: 0.92; 95% CI: 0.89–0.95) were all negatively associated with receiving FC testing.

FC Results and Subsequent IBD Diagnoses

The study also examined diagnostic outcomes among patients referred to gastroenterology, identifying differences according to FC concentration.

Among referred patients with FC levels above 250 µg/g, 23.7% received an IBD diagnosis. However, this proportion fell to 4.1% among those with intermediate FC levels of 100–250 µg/g.

Importantly, the findings also highlighted the diagnostic relevance of accompanying symptoms. Among patients presenting with rectal bleeding and FC levels of 100–250 µg/g, 9% were subsequently diagnosed with IBD.

Implications for Primary Care Referral Pathways

Despite normal FC results below 100 µg/g, 25.2% of symptomatic patients were still referred to secondary care. Among these referrals, 0.5% resulted in an IBD diagnosis and 1% in a colorectal cancer diagnosis.

The researchers concluded that FC testing could effectively support the triage of patients with suspected IBD in primary care. However, continued referrals following negative results suggested that clinicians considered additional clinical factors when determining the need for specialist assessment.

Overall, the findings highlighted the value of FC testing in primary care while identifying differences in testing uptake and referral patterns. Improving access to testing and understanding the factors influencing clinical decisions could help refine diagnostic pathways for patients presenting with lower GI symptoms.

Reference

Umar N et al. Fecal calprotectin testing for inflammatory bowel disease in patients presenting with lower gastrointestinal symptoms: a retrospective primary care cohort study in the United Kingdom. Inflamm Bowel Dis. 2026;DOI:10.1093/ibd/izag218.