Could you tell me what are requirements for blood transfusion?

Be a healthy adult.: You will be asked questions to be sure you are healthy, have not engaged in behaviors associated with viral illnesses like hepatitis or hiv, are not taking problematic medications and have not traveled to areas where malaria & other blood borne diseases are common. You have to have normal blood pressure and pass a blood test to be sure you are not anemic.

Need of blood : Blood transfusions are required when a patient's body can't maintain adequate oxygenation for tissues due to decreased red blood cells. Usually if hemoglobin levels are below 6 g/dl and there are symptoms of anemia or active bleeding, a transfusion maybe required in order to save his or her life.