Validation of the diagnostic accuracy of neutrophil to lymphocyte ratio (NLR) and mean platelet volume (MPV) in cirrhotic patients with spontaneous bacterial peritonitis

Background Spontaneous bacterial peritonitis (SBP) is a significant complication among cirrhotic patients with ascites and is associated with high mortality. Early diagnosis and treatment of SBP are crucial, as they are associated with better outcomes and lower mortality. The neutrophil-to-lymphocyte ratio (NLR) and mean platelet volume (MPV) are routine, inexpensive, easily measured markers readily obtained from a complete blood count (CBC). Several studies have addressed the diagnostic role of NLR and MPV in patients with SBP but with different cutoff values, sensitivity, and specificity. Therefore, we conducted this study to validate the clinical utility of NLR and MPV in diagnosing SBP. Methods This study included 332 cirrhotic patients with ascites who were admitted to Sohag University Hospitals in Egypt between April 2020 and April 2022. Of these patients, 117 had SBP, and 215 did not. Both NLR and MPV were measured in all patients, and the ability of NLR and MPV to diagnose SBP was assessed using the receiver operator characteristic (ROC) curve analysis. Results NLR and MPV were significantly elevated in patients with SBP compared to those without SBP ( P < 0.001). At a cutoff value of 5.6, the sensitivity and specificity of the NLR in detecting SBP were 78% and 81%, respectively. In contrast, MPV, at a cutoff value of 8.8 fL, had a sensitivity of 62% and a specificity of 63%. The combination of NLR and MPV did not provide significant additional diagnostic value beyond only using NLR. Conclusion Although NLR and MPV allow the detection of SBP, the NLR has higher clinical utility and is superior to MPV in diagnosing SBP.