If identified, the cause of the anemia Etiology of Anemia Anemia is a decrease in the number of red blood cells (RBCs), which leads to a decrease in hematocrit and hemoglobin content. (See also Red Blood Cell Production.) The RBC mass represents the... read more 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)
Transfusion procedures Technique of Transfusion CAUTION: Before transfusion is started, consent should be obtained, and the patient’s wristband, blood unit label, and compatibility test report must be checked at the bedside to ensure that... read more and blood components Blood Products Whole blood can provide improved oxygen-carrying capacity, volume expansion, and replacement of clotting factors and was previously recommended for rapid massive blood loss. However, because... read more are discussed elsewhere, as is the evaluation of anemia Evaluation of Anemia Anemia is a decrease in the number of red blood cells (RBCs) as measured by the red cell count, the hematocrit, or the red cell hemoglobin content. In men, anemia is defined as any of the following... read more 
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