Do You Need a Blood Transfusion?

Low Red Blood Cell Count

If you have a low red blood cell count (anemia), your doctor will measure how serious your condition is by testing your blood to find out the size, shape, and number of red blood cells. The doctor will also measure the following:

• Hemoglobin (Hb) - Hemoglobin is the substance inside red blood cells that carries oxygen and gives red blood cells their color.
• Hematocrit (Hct) - Hematocrit is the percentage of your blood that is made up of cells rather than plasma.

If you don’t have enough red blood cells, your bloodstream cannot carry enough oxygen to all of the tissues in your body. This can make you feel tired, dizzy, lightheaded, or weak.

The doctor will decide whether you need a red blood cell transfusion based on many factors. For example, he or she will consider when your low red blood cell count started and how well your body is coping with it. For example, if your hemoglobin level is low but you are not experiencing any symptoms (such as dizziness or shortness of breath), you might not need a red blood cell transfusion. But if you have a heart or lung disease, you might need a transfusion even if your hemoglobin level is not low enough to cause symptoms.

Low Platelet Count

If your bone marrow is not making enough platelets because of chemotherapy or radiation therapy, your blood will not clot normally when you are cut. To find out whether you need a platelet transfusion, your doctor will measure your platelet count. If it is very low, the doctor will consider a platelet transfusion if he or she believes that you are at risk of dangerous bleeding during surgery. But if your platelet count is low and you do not have any signs of bleeding, you might not need a platelet transfusion.

Low Plasma and Cryoprecipitate Count

In addition to platelets, you need plasma and cryoprecipitates to clot blood normally. If you bleed a lot or don’t have enough blood-clotting factors, your doctor might order a plasma or cryoprecipitate transfusion.

Low White Blood Cell Count

If you receive chemotherapy or radiation, your doctor will monitor the number of neutrophils (white blood cells that your body needs to fight infection) or granulocytes. If you have a low neutrophil count, you are more likely to have a serious infection. This condition is known as neutropenia.

In the past, your doctor might have recommended a transfusion of granulocytes for neutropenia. But this type of transfusion is no longer very common because it isn’t clear that it helps reduce the risk of infection. Also, granulocyte transfusions have side effects, such as fever, and can sometimes pass on certain infectious diseases that are particularly dangerous for people with weak immune systems. For these reasons, most doctors recommend treatments other than granulocyte transfusions to treat low white blood cell counts.