Unveiling the Power of CBC: Platelet-To-Lymphocyte Ratio as a Game-Changer in Late-Onset Neonatal Sepsis Diagnosis

Objective This study evaluated the diagnostic utility of novel parameters derived from complete blood count (CBC) analysis, including the nucleated red blood cell count (NRBC), neutrophil-to-lymphocyte ratio (NLR), red cell distribution width (RDW), plateletcrit (PCT), and platelet-to-lymphocyte ratio (PLR), in identifying late-onset neonatal sepsis (LOS). Methods This was a retrospective, single-center, case‒control study in a tertiary neonatal intensive care unit. The study included 38 neonates diagnosed with LOS and 22 healthy control subjects. The data collected included demographic characteristics, clinical findings, and laboratory values, including CBC-derived parameters, C-reactive protein (CRP) levels, and blood cultures. Statistical analyses were performed to assess differences between groups and the diagnostic performance of key parameters via receiver operating characteristic (ROC) curves. Results Significant differences in multiple parameters were observed between the LOS and control groups. Elevated CRP, platelet count, PCT, lymphocyte percentage, and PLR, in addition to decreased hemoglobin, hematocrit, neutrophil percentage, NRBC percentage, and NLR, were associated with LOS. PLR demonstrated the strongest diagnostic utility, with a cutoff value of 45.24 achieving 81.6% sensitivity, 61.9% specificity, and an area under the curve (AUC) of 0.787 (95% CI: 0.671–0.903). Logistic regression analysis revealed that the PLR was the most significant independent predictor of LOS (OR: 1.071; 95% CI: 1.009–1.135, p = 0.023). Conclusion CBC-derived parameters, particularly the PLR, offer promising diagnostic value for LOS. These findings support incorporating these accessible and cost-effective biomarkers into clinical practice for the early diagnosis and management of LOS, warranting further validation in larger, multicenter studies.