Investigation of Clinical and Laboratory Symptoms in Rapid Diagnosis of Neonatal Sepsis

Objectives: Neonatal sepsis is associated with significant mortality and morbidity, and its rapid diagnosis remains a clinical challenge due to the non-specific nature of its symptoms. The hematological scoring system (HSS) is a low-cost, rapid diagnostic tool based on a complete blood count (CBC). This study aimed to investigate clinical and laboratory findings and to evaluate the diagnostic accuracy of HSS in the rapid diagnosis of neonatal sepsis in a tertiary care center. Materials and Methods: This cross-sectional-analytical study was conducted on 80 neonates (aged <28 days) with suspected sepsis admitted to Tabriz children’s hospital. Based on blood culture results, infants were divided into two groups: definite sepsis (n=3) and non-sepsis (n=77). Clinical symptoms and laboratory parameters (including CBC and CRP) were recorded, and the HSS score was calculated for each infant. The diagnostic accuracy of HSS was evaluated using receiver operating characteristic (ROC) analysis, and indices such as sensitivity and specificity were calculated. Results: The mean gestational age and birth weight were significantly lower in the sepsis group (P<0.001). Gram-positive cocci, specifically Staphylococcus aureus (Coagulase-positive), were the most common causative agents (n=2, 66.7%), followed by Klebsiella pneumoniae (n=1, 33.3%). Among clinical signs, lethargy, hypothermia, and cyanosis were significantly more frequent in the sepsis group (P < 0.05). CRP, I/T ratio, and HSS scores were significantly higher, and platelet counts were lower in the sepsis group (P < 0.001). The ROC curve for HSS showed an area under the curve (AUC) of 0.88. At the optimal cut-off point (≥4), sensitivity was 100% (95% CI: 43.9–100), specificity 83.1%, positive predictive value (PPV) 15.8%, and negative predictive value (NPV) 100%. Conclusions: In this cohort with a low prevalence (3.75%) of culture-proven sepsis, the HSS demonstrated high diagnostic accuracy, particularly with a perfect sensitivity and NPV within our limited sample, effectively ruling out sepsis when the score is low. Incorporating this simple, inexpensive tool into clinical assessment may improve decision-making regarding antibiotic initiation and reduce unnecessary antibiotic exposure. However, the precision of sensitivity and PPV estimates is limited by the small number of sepsis-positive cases.