Evaluation of neutropenia and neutrophilia in preterm infants

Objective: Neutrophil counts are used routinely as part of the sepsis evaluation in newborn infants. In this article, we review the normal blood neutrophil concentrations and the clinical approach to neutropenia and neutrophilia in the neonatal period. Methods: A literature search was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies. Results: Neutropenia and neutrophilia are documented frequently in premature infants. Neutropenia can be seen in up to 8% of all infants admitted to neonatal intensive care. Neutrophilia is even more common, reported in up to 40% of all preterm infants. Conclusions: Neutrophil counts should be carefully evaluated in premature neonates. Maternal and perinatal history, physical examination, and a limited laboratory assessment is usually adequate for making a diagnosis in most infants.