Ascitic Fluid Calprotectin Level as a Diagnostic Marker of Spontaneous Bacterial Peritonitis in Cirrhotic Patients

Background:Spontaneous bacterial peritonitis (SBP) is the infection of pre-existing ascitic fluid without evidence of a secondary infection. Objective: To evaluate ascitic fluid calprotectin as a diagnostic marker of spontaneous bacterial peritonitis in cirrhotic patients. Patients and Methods: This study was conducted on 50 cirrhotic patients with ascites. Patients were divided into 2 groups: Group (I):Included40 cirrhotic patients with SBP on the basis of polymorphonuclear leukocytes (PMN) count in the ascitic fluid ≥250 cells/μLin the absence of secondary peritonitis, irrespective of ascitic fluid culture results, Group (II):Included10 cirrhotic patients with ascites but without SBP (control group). Results: There was a statistically significant difference between the two studied groups regarding hemoglobin (Hb) (P=0.006), white blood cells (WBCs) (P=0.015), platelet count (P>0.001), C-reactive protein (CRP) (P=0.001) and bilirubin (P=0.013). There was also significant difference between the two studied groups regarding ascitic fluid analysis parameters; as ascitic lactate dehydrogenase (LDH) and PMN count were significantly higher in SBP group (P<0.001, for both). Ascitic fluid calprotectin was significantly higher in SBP group compared to non-SBP group (26.3 ng/ml (6.5 – 75) vs. 15 ng/ml (6.5-33); P=0.013). Ascitic calprotectin was significant at a cutoff level of 18 ng/ml with a sensitivity of 90% and 70% specificity for diagnosing SBP with an area under the curve (AUC) = 0.835). Conclusion: Ascitic fluid calprotectin could be used to serve as a convenient reliable diagnostic marker for SBP in cirrhotic patients with ascites.