Red blood cell

Red blood cells (RBCs), also known as erythrocytes, are cells that carry oxygen by means of hemoglobin, and form part of the cellular component of blood as it circulates throughout the body. These extremely common cells are typically made in the bone marrow in a process called erythropoiesis. During this process in humans, the red blood cell nuclei are expelled.

Labeled erythrocytes are often used in nuclear medicine, e.g. Tc-99m labeled erythrocytes can be used to assess GI bleeding.  Normal red blood cells live about 120 days before destruction, however certain diseases will alter the survival time of these cells.

Erythrocytes are typed by their surface antigens (which define blood groups) for blood transfusion.