Peripheral White Blood Cell Count and Differential Count
Total white blood cell counts have little value in the diagnosis of early-onset sepsis and have a poor positive predictive accuracy.Many investigators have analyzed subcomponents
of the white blood cell count (neutrophil indices)—absolute neutrophil count,
absolute band count, and immature to total neutrophil (I/T)ratio—to identify infected infants. Like most diagnostic tests for neonatal sepsis, neutrophil indices have proven most useful for excluding infants without infection rather than identifying infected neonates. Neutropenia
may be a better marker for neonatal sepsis and has better specificity than an elevated neutrophil count, because few conditions besides sepsis(maternal pregnancy-induced hypertension,
asphyxia, and hemolytic disease) depress the neutrophil count of neonates.