Background and study aims: Familial Mediterranean fever (FMF) is an autoinflammatory disease presented  by inflammatory attacks. Calprotectin (FC) is a calcium-binding protein that is found mainly in neutrophils, in monocytes and reactive macrophages. It considered a cytokine released from monocytes and neutrophils as a result of  tissue trauma and inflammation. This study aimed to investigate fecal calprotectin levels in FMF patients as predictor of disease activity.
Patients/Material and Methods: This is a Prospective cross-sectional study. Between May 2020 and May 2022, 158 patients diagnosed with FMF in our outpatient clinic in Kafrelsheikh university hospital after confirmation by PCR and obtaining Medical consent for participation in this study. Blood was collected from a peripheral vein to complete blood picture, ESR, CRP, Amyloid A, Faecal calprotectin. Blood tests were examined by ELISA; the study protocol was approved by the local ethics committee.‎
Results: We enrolled 158 patients among them 102 patients were females, and 56 were males. Largest number of patients was diagnosed at age of twenties. Attacks last in 116 patients for less than 48 hours, while lasting for more than that in 42 patients. 130 patients had heterozygous mutation(Group 1), 28 patients had homozygous mutations(Group 2) confirmed by PCR . There was a statistically significant difference between the two groups in Fecal calprotectin level at time of diagnosis  (P < 0.001616). The level Calprotectin at time of diagnosis of 100 pg/mL had 96.40% sensitivity and 96.60% Specificity. Homozygous mutation had positive correlation with Colchicine dose needed to give response. Calprotectin level have negative correlation with Colchicine dose needed‎.
Conclusion: Our finding suggests that fecal calprotectin can be used to assess the diagnosis and severity of FMF patients. However, future studies are recommended ‎.