Persistent Calprotectin Elevation After Infection Clearance

Inflammatory Bowel Disease (IBD)

Persistently elevated calprotectin (>150 mg/g) in asymptomatic patients predicts disease relapse with a 4.4-fold increased risk in ulcerative colitis, according to the American Gastroenterological Association 1, 2
The infection may have unmasked underlying IBD or triggered post-infectious IBD, as suggested by the American Gastroenterological Association 3, 4
Calprotectin >150 mg/g warrants endoscopic evaluation to assess for chronic inflammatory conditions, as recommended by the American Gastroenterological Association 4, 5

For persistent calprotectin elevation 10 months post-infection, repeat calprotectin measurement to confirm persistent elevation (not transient), as suggested by the American Gastroenterological Association 4, 5
If calprotectin >150 mg/g on repeat testing, proceed with endoscopic evaluation to assess for chronic inflammatory conditions, as recommended by the American Gastroenterological Association 4, 5

False positive rates are substantial: 18-26% in asymptomatic patients depending on cutoff used, according to the American Gastroenterological Association 6, 7

A calprotectin level >150 μg/g indicates active inflammatory disease requiring endoscopic assessment, according to the American Gastroenterological Association 8
A calprotectin level between 50-150 μg/g requires clinical correlation with symptoms, and repeat measurement in 3-6 months if asymptomatic, or endoscopic evaluation if symptomatic, as recommended by the American Gastroenterological Association 8
A calprotectin level <50 μg/g essentially rules out significant ongoing inflammation, as stated by the American Gastroenterological Association 9

Calprotectin is more sensitive than CRP for detecting intestinal inflammation, and CRP should not be relied upon alone for diagnosis, as noted by the American Gastroenterological Association 10, 9