[The predictive values of total white blood count and differential count in the diagnosis of early-onset neonatal sepsis]

Abstract

Early-onset neonatal sepsis (EONS) is one of the most common diagnostic challenges in neonatal population. Aims of this study was to analyse values of total white blood count (WBC) and differential count in neonates with EONS and to determine cut-off values with the highest accuracy in diagnosis of infection.

Patients and methods: In the retrospective-prospective research we include 341 neonates born from 37th to 42nd week of gestational age, with one or more obstetric risk factors for EONS, in single pregnancy, both genders and without visible anomalies. Capillary blood samples for analysed parameters levels were obtained in the first 72 hours of life. A diagnosis of EONS was based on microbiological findings, clinical signs and radiography of chest.

Results: Obstetric risk for EONS at delivery had 341/12 298 (2.8%) neonates, and EONS occurred in 199/341 (58.4%) neonates. The mean total WBC count was 22.5 +/- 9.5 x 109/L, the mean absolute mature neutrophil count was 13.9 +/- 6.8 x 109/, while the mean total neutrophil count was 15.6 +/- 7.8 x 109/L. Neonates with EONS had medial of total immature neutrophil count of 1.2 x 109/L, immature to total neutrophil ratio (I:T ratio) of 0.09 and medial of immature to mature neutrophil ratio (I:M ratio) was 0.10. ROC curve analysis cut-off values of I:T (> 0.08) and I:M (> 0.09) ratio had acceptable accuracy in the diagnosis of EONS. The value of total WBC > 26.4 x 109/L, with accuracy of 88% predict EONS. High predictive value (82.9%) in EONS had total neutrophil count value of more than 17.6, and total immature neutrophil count value of more than 1.1 x l09/L predict presence of EONS with accuracy of 65.3%. Cut-off values of I:T (66.8%) and I:M (67.3%) ratio almost in the same percent predict EONS. In univariable predictive model, only cut-off value of mature neutrophil count was not significant in the detection of EONS, while cut-off values of other analysed parameters had significant predictive value (p < 0.05).

Conclusion: Total white blood count and differential count are changed in neonates with early-onset neonatal sepsis. The predictive value of analysed parameters cut-off values is important in everyday work of neonatology's to make difference among infected and non-infected neonates.