Extremely low birth weight preterm infants, those weighing less than 1000 g at birth, have low blood volumes at birth, and their care requires frequent removal of blood for laboratory tests. Virtually all of these infants are transfused, but at inconsistent hemoglobin thresholds.
Eligible infants (< 1000 g and <29 weeks gestation) enrolled in the TOP Trial are randomly assigned to receive red blood cell transfusions according to one of two strategies based on the hemoglobin threshold for transfusion: either high hemoglobin (liberal) or low hemoblogin (restrictive) threshold. It is unknown which transfusion strategy is superior. TOP is powered to demonstrate which strategy minimizes the primary outcome of death or neurological disability in survivors at 22-26 months (age corrected for prematurity).