Diagnostic Value of Fecal Calprotectin in Preterm Infants with Necrotizing Enterocolitis

Background: Necrotizing enterocolitis (NEC) is the most commonly acquired gastrointestinal emergency among neonates. However, the present diagnosis methods of NEC are non-specific and do not provide sufficient insight into the early discrimination. Fecal calprotectin (FC) is an intestinal-specific biomarker and has been used to differentiate different intestinal diseases. The aim of this study is to evaluate the value of FC as an early indicator for the identification of NEC. Methods: A total of 40 preterm infants were recruited, including 17 cases with NEC and 23 normal preterm infants. At enrollment, the clinical features, radiological finding, serological test, and other test results of subjects were recorded. FC concentration assays were performed by enzyme-linked immunosorbent assay (ELISA). The classification of the NEC was confirmed with the modified Bell staging criteria. Results: The median FC levels in the NEC group were significantly higher than those in the non-NEC group (858 (347.5, 1417.5) vs. 179 (125,265) mu g/g, p < 0.001). There was statistical difference in stage I, II, and III of NEC (chi(2) = 6.672, p = 0.036), the median FC levels were 457 (309, 875), 932 (532, 1712), and 3108 (1378, 4276) mu g/g, respectively. FC levels were correlated negatively to platelet counts (r = -0.491, p = 0.001), and positively to CRP (0.357, p = 0.024). The ROC curve defined a cutoff of 281 mu g/g for NEC in preterm infants (Z = 11.737, p < 0.001), the area under the curve (AUC) (95% confidence interval) was 0.931 (0.804, 0.987), and the sensitivity and specificity were 88.24% (63.6%, 98.5%), 82.61% (61.2%, 95.0%), respectively. Conclusions: FC concentration is a useful, safe, and noninvasive test. It increases in preterm infants with NEC and has the potential to diagnose NEC early and to remind us of the severity of NEC in preterm infants.