When are blood transfusions needed?

Acute or chronic?: Blood transfusions are needed for various reasons, including anemia, acute blood loss from injury, internal bleeding, rectal bleeding, blood in your urine, etc. It depends on how low the blood count (hemoglobin) is and how quickly the hemoglobin has dropped. There is professional debate on the exact number (of hemoglobin) for when to transfuse blood.

Decreased oxygen lev: This is a clinical decision since patients with symptoms of hypoxemia(low oxygen) most likely will not improve until their oxygen carryin capacity (red blood cells and hemoglobin) are increased to support the normal function of the body. In cases of acute bleeding of 2 or more liters of blood, the patient most likely will need a transfusion (our body has 4-6 liters of blood or 10 pints).