Blood transfusion is commonly used to treat anemia in intensive care units (ICUs). By ICU day three, 95% of all ICU patients have an abnormal hemoglobin level. After a 1-week stay in the ICU, patients have an 85% chance of being transfused. According to the American Red Cross, 14 million units of packed red blood cells (PRBCs) are transfused every year in the United States. Blood component therapy can be a lifesaving measure in many patients and these transfusions have a sound physiologic rationale: to increase hemoglobin and oxygen-carrying capacity. However, blood transfusion poses significant risks including viral transmission, hemolytic transfusion reaction, volume overload, and the uncommon but devastating clerical error leading to an ABO-incompatible transfusion. Transfusion of PRBCs in the intensive care unit is associated with increased nosocomial infections, diminished organ function scores, and ICU mortality.

As stated above, hemoglobin levels decrease in ICU, even in non-bleeding patients. A large percentage of this blood loss is associated with phlebotomy, which accounts for 30% of all blood transfused in the ICU. The number of blood draws and the volume of blood drawn correlate with worse ICU organ dysfunction scores. Attempts to decrease red blood cell loss from phlebotomy in the ICU can be wide ranging.