Reference values of blood cell counts in the first days of life.

The lack of updated neonatal reference values for hematological parameters impacts significantly with clinical management of both healthy and sick newborns. The present pilot study was thus aimed at assessing updated hematological Italian reference values in late preterm and term newborns. From January 2004 to December 2008 hematological laboratory tests were performed in 1175 newborns (820 healthy and 355 sick controls) between 33-41 weeks of gestation, during the first four days after birth. Hematological parameters were sorted for gender and gestational age and statistically analyzed. No gender-related differences were observed at different weeks of gestation and no significant differences were found when study population was sub-grouped for late preterm and term newborns. During the first 4 days of life erythrocytes and platelets remained stable whilst white blood cell counts and differentials were significantly modified. This study shares updated reference values for hematological parameters in the early phases after birth and offers additional support for improving the management of sick infants.