Aim of the study:
Aim of this study was to evaluate whether fecal calprotectin (FC) can be used as non- invasive biomarker of allergic enterocolitis and be helpful in differentiating with other inflammatory gastrointestinal conditions.

Material and methods:
The retrospective study was performed on the group of 48 children, aged 1–36 months (mean 9.0 ±6.6) admitted to our Department for diagnostics of complaints from gastrointestinal tract. The inclusion criteria to analysis was the increased FC concentration (> 150 µg/g of stool) evaluated using ELISA method. Subjects were reviewed for the diagnosis, gastrointestinal symptoms, infectious parameters and allergic tests. The study group was then divided into three subgroups considering the cause of the increased FC concentration including 17 children with food allergy, 10 with infection and 14 with both of them. Seven children were excluded from the study due to the other diagnosis; 18 healthy, age comparable children, were qualified to the reference group.

Results:
FC concentration was significantly higher in the group of children with allergy (mean 892.3 ±791.4 µg/g, p < 0.001), infection (mean 742.2 ±900.7 µg/g, p = 0.046) and both diagnosis (mean 1088.7 ±528.3 µg/g, p < 0.001) in comparison to the reference group (mean 81.5 ±37.3 µg/g), but no significant statistical differences were found between subgroups regarding to the cause of gut inflammation (p > 0.05). The main cause of infection was Staphylococcus aureus (50.0%); of allergy – cow’s milk. The concentration of C-reactive protein was higher in the group of children with infection compared to allergic patients (14.3 ±32.5 mg/l vs. 3.1 ±3.7 mg/l; p = 0.305).

Conclusions:
Food allergy as well as infection can be a cause of increased FC concentration. FC might only be useful as a screening test of allergic enterocolitis in infants and young children.