Calprotectin Measurement in Ascitic Fluid: A New Test for the Rapid Diagnosis of Spontaneous Bacterial Peritonitis

Introduction: Spontaneous bacterial peritonitis (SBP) is diagnosed by the presence of 250 polymorph nuclear cells (PMN) per milliliter (ml) in ascitic fluid. However, the procedure is time-consuming, operator-dependent, and not always readily available. Calprotectin is a cytosolic protein in neutrophilic leukocytes that is released in response to inflammatory processes. In the GI tract calprotectin in feces is considered a valid marker of intestinal inflammation. Aims and Methods: The study aimed to assess the role of calprotectin concentrations in ascites for the diagnosis of SBP. Forty patients [mean age 50±2 years, 10 (25%) females] with HCV liver cirrhosis. Who were referred for paracentesis were included in this study; the following investigations were performed: Serum-ascites albumin gradient, ascitic PMN cell count (microscopic handcount), bacterial cultures and cyto-logical analysis. In addition, ascitic calprotectin was measured using an enzyme-linked immunosorbent assay (ELISA). Results: Ascitic calprotectin values measured by ELISA correlated well with PMN cell count (p-value=0.001, rho—F0.729). Calprotectin levels of patients with PMN 250/m1 (N=8, 20%) were higher than in patients with PMN 250/ml (N=32, 80%). Ascitic calprotectin values correlated well with albumin level (p-value=0.001, rho=-0.716). Conclusion: Measurement of calprotectin in ascites might be a valuable surrogate marker for PMN cell count. It might be valuable for the rapid diagnosis of SBP.