Objectives: To measure concentrations of fecal calprotectin (f-calprotectin) in infants with very low birth weight (VLBW; <1500 g) longitudinally and to describe changes in f-calprotectin in infants who develop severe abdominal disease.
Patients and methods: The study included 59 VLBW infants. Seven patients (disease group) developed severe abdominal disease defined as necrotizing enterocolitis (NEC) or a condition leading to laparotomy. The remainder (n = 52) were considered reference infants and had a mean (+/-SD) gestational age of 27.2 +/- 2.6 weeks and a birth weight of 939 +/- 273 g. F-calprotectin was analyzed in meconium and weekly during postnatal weeks 1 to 8. In disease cases, more frequent samples were analyzed around the time of abdominal disease diagnosis.
Results: In reference infants the median (range) f-calprotectin level in meconium was 332 (12-9386) microg/g and correlated negatively to Apgar score. F-calprotectin in postmeconium samples was 253 (9-1867) microg/g and correlated positively to delivery by cesarean section, postnatal age, and volume of enteral feeds, and negatively to treatment with antibiotics and corticosteroids. In reference infants no postmeconium sample had f-calprotectin levels >2000 microg/g. In disease cases f-calprotectin was increased to >2000 microg/g in 3 cases of NEC and 1 case of covered perforation with microscopic bowel inflammation. In 1 case of NEC without microscopic bowel inflammation and 2 cases of focal intestinal perforation, f-calprotectin levels never exceeded 2000 microg/g.
Conclusions: F-calprotectin concentrations in VLBW infants are similar to previously reported levels in healthy term and moderately preterm infants. An f-calprotectin level >2000 microg/g is a useful but not an early marker of NEC and other severe intestinal inflammatory conditions in VLBW infants.