A newborn screening sample should be taken on every infant prior to discharge. If this happens before 24 hours, parents should be informed that a repeat newborn screen after 24 hours must be done and informed how to complete the newborn screen.
If possible, it is best to take the newborn screening sample prior to a packed red blood cell (PRBC) transfusion. PRBC transfusions are known to affect the results of hemoglobin and galactosemia screens. If the newborn screen has been taken after a PRBC transfusion, a repeat sample should be taken 4 months after the last transfusion to complete screening.
Premature or Very Low Birth Weight Infant
For infants who are premature (gestational age at birth is less than 33 weeks) or very low birth weight (<1500g) it is recommended that a first newborn screening sample be collected between 24 and 48 hours of age and a second sample collected at 3 weeks of age. Details on this recommendation can be found in the Newborn Screening Manual (link).