Elevated Ascitic Fluid Lactoferrin Levels as a Diagnostic Marker for Spontaneous Bacterial Peritonitis in Cirrhotic Patients

Background: Spontaneous bacterial peritonitis (SBP) is a severe infection in cirrhotic patients with ascites, often leading to decompensation and poor outcomes. Current diagnostic methods rely on ascitic fluid (AF) polymorphonuclear cell (PMN) counts and culture results, which are time-consuming and have limitations. Lactoferrin, an iron-binding glycoprotein released from neutrophils during degranulation, has emerged as a potential biomarker for SBP diagnosis. Objective: This study aimed to assess the diagnostic accuracy of AF lactoferrin as a biomarker for the rapid detection of SBP in cirrhotic patients with ascites. Patients and Methods: This prospective study included 60 patients with decompensated liver cirrhosis and ascites, 30 with SBP (PMN ≥ 250/mm³ or culture-positive neutrocytic ascites) and 30 without SBP. Patients underwent clinical, laboratory, and AF analyses. AF lactoferrin levels were measured using ELISA, and diagnostic accuracy was assessed using receiver operating characteristic (ROC) curve analysis. Results: The median AF lactoferrin level was considerably higher in the SBP group compared to controls (217.5 ng/mL vs. 50.0 ng/mL, p < /em> < 0.001). At a cut-off of ≥75 ng/mL, lactoferrin demonstrated a sensitivity of 85% and specificity of 100% (AUC = 0.896, p < /em> < 0.001). AF PMN and total leukocyte counts also correlated strongly with lactoferrin levels (r = 0.581, p < /em> < 0.001 and r = 0.634, p < /em> < 0.001, respectively). Conclusion: AF lactoferrin is a reliable, rapid biomarker for SBP diagnosis with excellent sensitivity and specificity. Its clinical utility may enhance timely detection and management of SBP in cirrhotic patients, potentially improving outcomes.