White blood cell the complete blood count. The normal white cell count is usually between 4 × 10/L and 1.1 × 10/L. In the US, this is usually expressed as 4,000 to 11,000 white blood cells per microliter of blood. White blood cells make up approximately 1% of the total blood volume in a healthy adult, making them substantially less numerous than the red blood cells at 40% to 45%. However, this 1% of the blood makes a large difference to health, because immunity depends on it. An increase in the number of leukocytes over the upper limits is called leukocytosis. It is
Neonatal red cell transfusion Neonatal red cell transfusion Neonates are defined as babies up to 28 days after birth. Most extremely preterm babies (less than 28 weeks) require at least one red cell transfusion, this is partly due to the amount of blood removed with blood samples compared to the baby's total blood volume (iatrogenic anemia) and partly due to anemia of prematurity. Most transfusions are given as small volume top-up transfusions to increase the baby's hemoglobin above a certain pre-defined level, or because the baby is unwell due to the anemia. Possible side-effects of anemia in babies can be poor growth, lethargy and