Objective: This study was planned to determine whether complete blood count parameters and scores based on complete blood count can be used as a diagnostic marker in neonatal sepsis.
Methods: This retrospective study included 70 patients with neonatal sepsis (Group 1) and 65 healthy neonates (Group 2) with similar age, sex, birth weight, and gestational age. The demographic data, blood culture results, clinical and laboratory findings were obtained from the medical records. Scores based on complete blood count such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), eosinophil-to-lymphocyte ratio (ELR), basophil-to-lymphocyte ratio (BLR) and monocyte-to-lymphocyte ratio (MLR) were calculated by dividing the number of neutrophils, platelets, eosinophils, basophils and monocytes by the number of lymphocytes, respectively.
Results: There were no significant differences between the groups in terms of demographic characteristics such as age, gender, birth weight, type of delivery and gestational week. C-reactive protein level was significantly higher in the neonatal sepsis group (p 0.05). While NLR was significantly higher (2.19±1.39 vs 1.44±1.07, p<0.001), ELR was significantly lower (0.08±0.07 vs 0.09±0.05, p=0.007) in neonatal sepsis group. NLR was positively correlated while ELR, lymphocyte, platelet, eosinophil and monocyte counts were negatively correlated with CRP (p<0.05). According to the results of ROC curve analysis, CRP, NLR, ELR, neutrophil, lymphocyte, platelet, eosinophil and monocyte counts were significant parameters for the diagnosis of neonatal sepsis. Cut-off values were 6.09 mg/L for CRP (sensitivity 88.57%, specificity 100%, AUC: 0.964, p <0.001), 1.01 for NLR (sensitivity 78.57%, specificity 63.08%, AUC: 0.727, p <0.001, 0.079 for ELR (sensitivity 64.29%, specificity 56.92%, AUC: 0.634, p = 0.007), 4.66x109/L for neutrophil count (sensitivity 68.57%, specificity 61.54%, AUC: 0.683, p<0.001), 4.33x109/L for lymphocyte count (sensitivity 65.71%, specificity 60.00%, AUC: 0.668, p=0.001), 259.00x109/L for platelet count (sensitivity 62.86%, specificity 58.46%, AUC: 0.659, p=0.001), 0.27x109/L for neutrophil count (sensitivity 61.42%, specificity 69.23%, AUC: 0.708, p<0.001) and 1.33x109/L for monocyte count (sensitivity 62.86%, specificity 56.92%, AUC: 0.647, p=0.003)
Conclusion: Although their sensitivities and specificities lower than CRP; NLR, ELR, neutrophil, lymphocyte, platelet, eosinophil and monocyte counts can be accepted as adjunctive data that contribute to the diagnosis of neonatal sepsis. In particular, NLR seems to be the most useful complete blood count parameter in the diagnosis of neonatal sepsis with the highest sensitivity and specificity
