What is anemia?
person whose blood is low in red blood cells has anemia. Red blood cells carry oxygen (O2) to tissues and organs throughout the body and enable them to use the energy from food. Without oxygen, these tissues and organs—particularly the heart and brain—may not do their jobs as well as they should. For this reason, a person who has anemia may tire easily and look pale. Anemia may also contribute to heart problems.
Anemia is common in people with kidney disease. Healthy kidneys produce a hormone called erythropoietin, or EPO, which stimulates the bone marrow to produce the proper number of red blood cells needed to carry oxygen to vital organs. Diseased kidneys, however, often don’t make enough EPO. As a result, the bone marrow makes fewer red blood cells. Other common causes of anemia include blood loss from hemodialysis and low levels of iron and folic acid. These nutrients from food help young red blood cells make hemoglobin, their main oxygencarrying protein. Healthy kidneys produce a hormone called erythropoietin, or EPO, which stimulates the bone marrow to make red blood cells needed to carry oxygen throughout the body. Diseased kidneys don’t make enough EPO, and bone marrow then makes fewer red blood cells.
Healthy kidney� Normal EPO
Normal red blood cells
Diseased kidney Reduced EPO
Reduced red blood cells
U.S. Department of Health
� and Human Services
NATIONAL INSTITUTES OF HEALTH
National Kidney and Urologic Diseases Information Clearinghouse
What are the laboratory tests for anemia?
A complete blood count (CBC), a laboratory test performed on a sample of blood, includes a determination of a person’s hematocrit, the percentage of the blood that consists of red blood cells. The CBC also measures the amount of hemoglobin in the blood. The range of normal hematocrit and hemoglobin in women who have a period is slightly lower than for healthy men and healthy women who have stopped having periods (postmenopausal). The hemoglobin is usually about one-third the value of the hematocrit.
How is anemia treated?
If no other cause for anemia is found, it can be treated with a genetically engineered form of EPO. The EPO is usually injected under the skin two or three times a week. Patients on hemodialysis who can’t tolerate EPO shots may receive the hormone intravenously during treatment. The intravenous method, however, requires a larger, more expensive dose and may not be as effective. The U.S. Food and Drug Administration (FDA) recommends that patients treated with EPO therapy should achieve a target hemoglobin between 10 and 12 grams per deciliter (g/dL). Recent studies have shown that raising the hemoglobin above 12 g/dL in people who have kidney disease increases the risk of heart attack, heart failure, and stroke. People who take EPO shots should have regular tests to monitor their hemoglobin. If it climbs above 12 g/dL, their doctor should prescribe a lower dose of EPO. The FDA recommends that patients whose hemoglobin does not rise to the target level with normal doses of EPO ask their doctor to check for other causes of anemia.
When does anemia begin?
Anemia may begin to develop in the early stages of kidney disease, when a person still has 20 to 50 percent of normal kidney function. This partial loss of kidney function is often called chronic kidney disease (CKD). Anemia tends to worsen as kidney disease progresses. End-stage kidney disease, the point at which dialysis or kidney transplantation becomes necessary, doesn’t occur until a person has only about 10 percent of kidney function remaining. Nearly everyone with end-stage kidney disease has anemia.
How is anemia diagnosed?
If a person has lost at least half of normal kidney function and has a low hematocrit, the most likely cause of anemia is decreased EPO production. The estimate of kidney function, also called...