Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in bacterial infections: contributions to diagnostic strategies in a tertiary care hospital in Tunisia [version 1; peer review: 3 approved]

Background Bacterial infections continue to pose a global health challenge, driven by antibiotic resistance and septicemia. This study aimed to assess the diagnostic utility of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in bacterial infections versus non-infectious causes of inflammation. Methods A prospective study included 164 adult patients who were divided into two groups: a group of patients with confirmed bacterial infections and a second group of patients with other diagnoses (inflammatory pathologies, neoplasms, venous thromboembolic diseases, etc.). NLR and PLR values were compared between the bacterial infection group and the non-infectious causes group and the diagnostic performances of NLR and PLR for detecting bacterial infections were evaluated in comparison with other infection markers. Results NLR and PLR were significantly higher in bacterial infections (p < 10 ^-6), and NLR was correlated positively with inflammation markers. NLR and PLR demonstrated significant potential in diagnosing bacterial infections, with an AUC of 0.72 and 0.60, respectively, using the following cutoff values: 4.3 for NLR and 183 for PLR. Conclusion These findings underscore the importance of NLR and PLR as adjunctive tools for bacterial infection diagnosis.