Ascites fluid calprotectin level is highly accurate in diagnosing spontaneous bacterial peritonitis: a preliminary proof of concept prospective study

Ascites is the most common complication of liver cirrhosis. Spontaneous bacterial peritonitis (SBP) is a common complication of ascites. The diagnosis is made by an ascitic fluid polymorphonuclear (PMN) cell count of ≥ 250/mm³. However, no other diagnostic test is present for the diagnosis of SBP. The aim of the study present study is to assess the diagnostic yield of ascitic calprotectin in SBP, and to explore whether it can predict disease stage. We performed a single center proof-of-concept prospective study including all patients with cirrhosis and ascites who underwent paracentesis. Overall, 31 patients were included in the study. Eight patients had SBP vs. 23 patients without SBP. Ascitic calprotectin level was 77.4 ± 86.5 μg/mL in the SBP group, as compared to 16.1 ± 5.6 μg/mL in the non-SBP group (P = 0.001). An ascitic calprotectin cut-off value of > 21 μg/mL was associated with sensitivity and specificity of 85.7% and 89.5%, respectively, with ROC of 0.947 (95% CI 0.783 to 0.997, P < 0.0001). Notably, ascitic calprotectin did not had a prognostic value in cirrhosis stage and prognosis. Ascitic calprotectin was highly accurate in the diagnosis of SBP. It can be a serve as adjunct for indefinite cases of SBP.