Can fecal calprotectin serve as a screen for necrotizing enterocolitis in infants?

•Current assays for fecal calprotectin do not provide infant-specific cut-offs.•Literature suggests that fecal calprotectin may help screen for necrotizing enterocolitis (NEC).•Data from a reference laboratory and literature were used to propose cut-offs for infants.•We were unable to validate the proposed cut-offs to screen for NEC by retrospective analyses. Researchers are debating if fecal calprotectin results are useful for infant patients, especially in screening for necrotizing enterocolitis (NEC). Currently, none of the FDA-approved calprotectin assays provide a cut-off for infant patients. We retrospectively analyzed data from a reference laboratory and university hospital to investigate if a cut-off could be established for infant patients. Data from a national reference laboratory of 5144 test results for fecal calprotectin were analyzed for infant patients, and a cut-off was estimated based on the distribution of results. Additionally, a literature proposed cut-off of 226 μg/g was also considered. Validation of either cut-off was attempted by review of the electronic medical record of our university hospital for 110 infant patients with results for fecal calprotectin. Infants had a high percentage of elevated fecal calprotectin results when using the adult cut-offs set by the manufacturer. A cut-off of 247 μg/g was estimated based on the reference laboratory results for infants 0–2 months old, which is similar to a literature proposed cut-off of 226 μg/g. However, the positive predictive value (PPV) for both cut-offs was