The reference interval for TSH varies significantly by age, sex, hour of day, and ethnicity. Time of year does not affect the TSH reference interval, and age, sex, hour of day and time of year do not affect the free T4 reference interval.

Abnormal coagulation values at preterm birth do not predict bleeding during the first week. This suggests to us that bleeding in the days after preterm birth is not generally the result of in utero coagulopathy. These findings bring into question the value of coagulation screening of nonbleeding preterm infants and prophylactic FFP administration to those with abnormal values.

The new reference interval charts can help clinicians identify abnormalities in the reticulocyte parameters. This information could be of value in identifying and following neonates with various hematological problems including hemolytic disorders, occult hemorrhage, or iron deficiency or other limitations of erythrocyte production.