A recent study has shown some promise in detecting necrotizing enterocolitis (NEC) with a fecal biomarker, S100A12 (J Pediatr 2012; 161: 1059-64).
In this prospective study of 145 preterm infants with a birth weight <1500 g, stool samples were collected on alternated days for 4 weeks. Fecal S100A12 and calprotectin were measured. Calprotectin in previous studies has been shown to be a poor marker for NEC.
Fecal S100A12, also called calgranulin C, belongs to a novel group of proinflammatory molecules. It is released by activated or damaged cells under conditions of cell stress and indicates phagocyte-specific damage.
18 (12.4%) developed NEC. Fecal S100A12 levels were elevated in severe NEC and also at 4-10 days beforehand. The sensitivity, specificity, positive predictive values, and negative predictive values were 70%, 68%. 37%, and 89% respectively. Thus, there is limited utility of this stool test due to the limited sensitivity/specificity. There is substantial overlap between control patients and patients who developed NEC. Furthermore, fecal S100A12 levels are age-dependent. Generally, they are higher early in life, likely due to increased mucosal permeability.
Calprotectin levels were elevated at the onset of NEC (median 349 mg/kg) and 48 hours before onset (median 83 mg/kg). The difference at 48 hours prior to onset did not reach statistical significance.