If identified, the cause of the anemia is treated. When the hemoglobin (Hb) falls dangerously low (eg, < 7 g/dL [< 70 g/L] for patients without cardiopulmonary insufficiency or higher for patients with it), red blood cell (RBC) transfusion temporarily increases oxygen-carrying capacity. RBC transfusion should be reserved for patients
With or at high risk of cardiopulmonary symptoms
With active, uncontrollable blood loss
With some form of hypoxic or ischemic end-organ failure (eg, neurologic ischemic symptoms, angina, tachycardia in patients with underlying heart failure or severe chronic obstructive pulmonary disease)
RBC transfusion therapy can also be part of management for specific patients with sickle cell disease and thalassemia.
Transfusion procedures and blood components are discussed elsewhere, as is the evaluation of anemia.