Background and study aim: Spontaneous bacterial peritonitis (SBP) is an important cause of morbidity and mortality in cirrhotic patients with ascites. The diagnosis of SBP is based on PMN leukocyte cell count exceeding 250/μL in ascitic fluid. However, this procedure is time consuming as well as subjective. C-reactive protein (CRP) has been reported to be a reliable predictor of SBP and an index of therapeutic effectiveness in adults. Ascitic fluid calprotectin reliably predicts PMN count >250/μL, which may prove useful in the diagnosis of SBP. This work was planned aiming to evaluate both ascitic fluid calprotectin and serum CRP as accurate diagnostic laboratory markers for detecting SBP.
Patients and methods: From 140 patients; only 124 patients with ascites were included in this study. They were divided into SBP group including 70 patients (49 males and 21 females) and non-SBP group of 54 patients (25 males and 29 females). Serum CRP was determined by latex agglutination and ascitic fluid calprotectin was measured using an enzyme-linked immunosorbent assay.
Results : Ascitic fluid calprotectin and serum CRP were significantly higher in SBP patients in comparison with the non-SBP group (754.67 ±256.06 vs. 280.77 ±230.97 and 62.4 ±28.39 vs. 9.81 ±8.98) respectively. In addition, both were positively correlated with ascitic fluid proteins and PMN count as well as with each other. At a cutoff value of 270 mg/dl, ascitic fluid calprotectin had 86% specificity and 97.5% sensitivity for detecting SBP [Area under the receiver operating characteristics curve (AUC) = 0.924 with negative and positive predictive values (NPV, PPV) for ascitic calprotectin 96% and 69% respectively.
Conclusion : Ascitic fluid calprotectin and serum CRP may be used as accurate and reliable markers for the diagnosis of SBP.