The retrospective evaluation of the effectiveness of fecal calprotectin in the differential diagnosis in the children evaluated between 2015-2018 at İstanbul University İstanbul Faculty of Medicine General Pediatric Outpatient Clinic

INTRODUCTION: Fecal calprotectin is a noninvasive marker showing gastrointestinal inflammation. Although it is an important test in the diagnosis and follow-up of inflammatory bowel diseases, recently it has been shown that it also may be elevated in many other disease. Fecal calprotectin, which is relatively high in the first years of life and varies with age, does not have a reference range in children. AIM: In our study, it was aimed to evaluate the fecal calprotectin results of children and their complaints, the diagnoses they got and other related factors. It was thought to determine the cases which testing is more usefull in, it could prevent unnecessary fecal calprotectin analysis in differential diagnosis. METHODS:In our study, 118 children aged 0-18 years, who were evaluated in the General Pediatrics Outpatient Clinics of Istanbul Medical Faculty, Department of Child Health and Diseases between 2015 and 2018, were identified. 18 children could not be reached because their contact information was not up to date. The parents of 100 children were interviewed on the phone. Since 6 children had a history of chronic inflammatory disease and 1 child had an abdominal operation, they were not included in the study. The study was conducted with the data of 93 children. The data obtained from the hospital management and information system and interviews with the parents were analyzed with the SPSS 21 program. RESULTS:A total of 93 children, 48.4% (n=45) girls and 51.6% (n=48) boys, were included in the study. The ages of the children participating in the study ranged from 3 months to 204 months, with a mean of 8.5±5.2 years. 10.75% (n=10) of the children were 1 year old and below, 13.98% (n=13) were between 1 and 4 years old, 75.27% (n=70) were 4 years old and older. The most common complaints that caused the physician to look for fecal calprotectin were abdominal pain 40.9% (n=38), diarrhea 29% (n=27), 16.1% (n=15) bloody stools, respectively. The complaints of 78.4% (n=73) of the children were found to be related to GIS. The mean fecal calprotectin level of 93 children included in our study was 234.16 µg/gr (±383.99 SDS), and the median value was 66.00 µg/gr (IQR:30-190). The minimum value for fecal calprotectin that did not show normal distribution was 9.00 µg/gr, while the maximum value was 2088.00 µg/gr. Mean fecal calprotectin values of children aged one year and younger, 1-4 years old, and 4 years old and older were 333.9 µg/gr, 185.4 µg/gr and 229 µg/gr; respectively. A significant difference was found between the levels of children aged one year and younger and children aged 4 years and older (p=0.043). It was observed that 58.1% (n=54) of the children in our study were newly diagnosed. The mean and median fecal calprotectin values of the children who got diagnosed were between 307.7 and 79.5 µg/gr; 132.4-57 µg/gr were found in undiagnosed children (41.9%, n=39) (p=0.066). The most common new diagnosis was Inflamatory Bowel Disease(IBD) (14.8%, n=8). Familial Mediterranean Fever (12.9%, n=7) was the second. The fecal calprotectin value of those diagnosed with IBD was found to be significantly higher than the value of all other newly diagnosed patients (p=0.004). Similarly, when all diagnoses were grouped as gastrointestinal system(GIS)-related or non-GIS-related diagnoses, the mean rank of fecal calprotectin of children with GIS-related diagnoses was higher than the results of children without GIS-related diagnoses (p=0.003). CONCLUSION: In our study, fecal calprotectin results were found to be significantly higher in children 12 months and younger than other age groups. Fecal calprotectin elevation is significant in some GIS diseases, especially IBD. Therefore, the benefit of testing fecal calprotectin should be considered in patients without suspected IBD. As stated in the literature, fecal calprotectin elevation in some rheumatological diseases was not significant in our study. In this respect, studies with a larger sample size will be illuminating regarding the use of fecal calprotectin and reference values in the pediatric patient group. Key Words: child, diagnosis, faecal calprotectin, gastrointestinal symptoms, clinical application, diagnosis