Red Blood Cells

Author: Courtney Misher, MPH, BS R.T.(T)
Last Reviewed: December 02, 2022

Blood is made up of four parts. They are red blood cells, white blood cells, platelets, and plasma. A red blood cell is the part of your blood that makes it red. Hemoglobin is the protein that makes up red blood cells. Red blood cells carry oxygen from your lungs to the cells in your body. Red blood cells also move carbon dioxide back to your lungs where it is exhaled.

Red blood cells are made in the bone marrow, which is found inside your bones. They live for about 120 days. Eating foods rich in iron and vitamins, such as E, B2, B12, and B3, helps to maintain healthy red blood cells.

What is a normal red blood cell count?

A normal red blood cell count is between 12 to 18 g/dL. Your red blood cell count can be checked by drawing blood for a complete blood count (CBC). A CBC measures the levels of the components that make up your blood.

What causes a low red blood cell count?

There are a few medical issues that can lead to a lower-than-normal red blood cell count, also called anemia. There are many types and causes of anemia. Treatment of cancer and cancer itself can lead to anemia. Some cancers can lead to internal bleeding, which leads to blood loss that can result in anemia. Cancers that start in the bone marrow, such as leukemia, can affect normal blood production.

Treatments for cancer can also lead to anemia. Chemotherapy and radiation therapy can affect not just cancer cells, but also healthy cells. Because of this, both treatments can lead to anemia.

If you have anemia, you may feel very tired, look pale, or feel short of breath.

Who needs a red blood cell transfusion?

If your hemoglobin level is well below normal (often below 8g/dL), you may be given a blood transfusion. If you have a heart condition, your care team may choose to give you a blood transfusion if your hemoglobin is low, but not below 8g/dL. Blood transfusions are also used during surgery when the procedure results in blood loss.

The transfusion increases the number of red blood cells in your body. These cells can then help carry more oxygen throughout your body. This will give you more energy and will help resolve symptoms such as pale color and shortness of breath.

How is a red blood cell transfusion done?

Prior to receiving a blood transfusion, you need to have your blood type checked, which is done by having your blood drawn. Blood type is determined by which antigens are found on your blood. Blood that you receive will be checked to make sure it is a match for your blood. This is done in a laboratory that specializes in blood products.

Red blood cells are given through an intravenous (IV) line. The infusion starts slowly and your vital signs (temperature, heart rate, oxygenation, and blood pressure) are checked often to make sure that you are not having a reaction to the transfusion. The rate that the blood is infusing may be increased if you are not having a reaction. A blood transfusion can take a few hours.

What are the risks of having a red blood transfusion?

Although not common, there are risks to having a red blood cell transfusion. These include infection and reactions. If you start to have itching, chills, any new pain, nausea, trouble breathing, or your throat feels tight, let your care team know right away as these are symptoms of a reaction.

The blood you receive is collected from donors. All donated blood is tested for viruses, bacteria, and parasites. The risk of catching a virus or other infection from a blood transfusion is very low. This includes HIV and Hepatitis B and C.

Blood transfusion process. Blood Transfusion Procedure Information | Red Cross Blood Services. (n.d.). Retrieved November 21, 2022, from

Low Red Blood Cell Counts: Anemia. American Cancer Society. (2020, February 1). Retrieved November 18, 2022, from

NCI Dictionary of Cancer terms. National Cancer Institute. (n.d.). Retrieved November 17, 2022, from

Types of blood transfusions: Blood Transfusions for Cancer patients. American Cancer Society. (2016, June 20). Retrieved November 21, 2022, from

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