Evaluation of ascitic lactoferrin as a diagnostic marker for spontaneous bacterial peritonitis in patients with liver cirrhosis

Abstract Background The optimal cut-off level of lactoferrin in ascitic fluid is debatable for identification of spontaneous bacterial peritonitis (SBP). This study aimed to detect the cut-off level of lactoferrin in ascitic fluid and its role in the diagnosis of SBP in patients with liver cirrhosis. This case–control study was conducted on 100 adult cirrhotic patients of both sexes, with ascites. Group A included 50 patients without SBP, while Group B included 50 patients with SBP. The Child–Pugh score was calculated. Lactoferrin levels in ascitic fluid were evaluated. Optimal cut-off values for lactoferrin levels and ascitic polymorphonuclear cells (PMNs) were determined using area under the curve (AUC) and receiver operator characteristic (ROC) analysis. Results Ascitic PMNs and lactoferrin levels were significantly higher in group B ( p -value < 0.001). Based on the ROC curve, ascitic PMNs and lactoferrin can be used to discriminate patients of SBP at a cut-off level of > 203 cells/mm 3 and > 29.1 µg/mL, AUC = 0.99 and 0.91, respectively. A negative bacterial culture was detected in 68% of SBP patients, with no significant correlation observed between the results and lactoferrin levels or the presence of PMNs in the ascitic fluid. Conclusions Ascitic lactoferrin is a quick and accurate way to check for SBP in cirrhosis patients, but ascitic lactoferrin levels and ascitic fluid culture do not correlate. Additionally, ascitic fluid PMNs have a high sensitivity and specificity as a diagnostic marker for SBP.