Management of Elevated Faecal Calprotectin in Acute Settings

Interpretation of Elevated Faecal Calprotectin in Acute Presentations

In acute diarrhoea, calprotectin is likely to be elevated and will not discriminate between inflammatory bowel disease (IBD) and gastroenteritis, making stool culture and/or flexible sigmoidoscopy or colonoscopy the appropriate diagnostic investigations 1, 2

For patients with bloody diarrhoea, flexible sigmoidoscopy is indicated regardless of calprotectin result 1, 2
For patients with suspected acute infectious diarrhoea, obtaining stool cultures to identify bacterial pathogens is recommended 2
For patients with rectal bleeding, abdominal pain, change in bowel habit, weight loss, or iron-deficiency anaemia, faecal calprotectin is not sensitive enough to exclude colorectal cancer, and cancer pathway referral should be strongly considered rather than relying on calprotectin 1, 2

In patients with moderate to severe symptoms suggestive of IBD flare, faecal calprotectin >150 μg/g can be used to rule in active inflammation and inform treatment adjustment without routine endoscopic assessment 3, 4
In patients with mild symptoms, even with elevated calprotectin (>150 μg/g), endoscopic assessment is recommended rather than empiric treatment adjustment 3, 4

Repeat measurement of calprotectin may be valuable, and in patients with initially elevated calprotectin (≥100 μg/g), repeat testing after approximately 18 days showed reduction in 53% of patients 1, 2
For patients in symptomatic remission but with persistently elevated biomarkers, repeat measurement in 3-6 months may be a reasonable alternative to immediate endoscopic assessment 6

The appropriate cut-off for calprotectin should be determined locally but is generally between 100 and 250 μg/g stool 2
Variability between different assays, variability in levels from different stool samples from the same patient, lack of stability for samples kept at room temperature for more than a few days, and variation related to the interval between stools being passed are practical issues with faecal calprotectin testing 1