The reason for these symptoms is that there is a lack of red blood cells. Red blood cells carry oxygen, which is important for all of the body's functions. When there are fewer red blood cells, the body does not get all the oxygen it needs. If there is not enough oxygen, the kidneys will produce a hormone called erythropoietin. Erythropoietin is released into the bloodstream and travels to the bone marrow where red blood cells are made.
Erythropoietin signals the bone marrow to make more oxygen-carrying red blood cells.
As the kidneys fail, they stop cleansing toxins from your body. They also make less erythropoietin than they should. Fewer red blood cells are produced so the muscles, brain, and other parts of the body do not get the oxygen they need to function properly. However, certain medical conditions, or unexpected blood loss, may result in the need for a transfusion. In addition, if the vial has been shaken vigorously, the solution may appear to be frothy and should not be used.