Thrombocytopenia (low platelet count) is common in the neonatal intensive care unit. Commonly, the decision of when to transfuse platelets is based on platelet number. Recently, Christensen et al (2006) proposed using transfusion guidelines based on platelet mass rather than platelet number. By using platelet size as a guide of when to give platelets, we may be able to decrease the amount platelet transfusions needed.