Why would a person need a red blood cell transfusion?

Patients who benefit most from transfusion of red blood cells include those with chronic anemia resulting from kidney failure, malignancies, or gastrointestinal bleeding and those with acute blood loss resulting from trauma. Since red blood cells have reduced amounts of plasma, they are well-suited for treating anemic patients who have congestive heart failure or who are elderly or debilitated; such patients may not tolerate the increased volume provided by whole blood.