Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues.

See also:

Anemia due to B12 deficiency

Anemia due to folate deficiency

Anemia due to iron deficiency

Anemia of chronic disease

Hemolytic anemia

Idiopathic aplastic anemia

Megaloblastic anemia

Pernicious anemia

Secondary aplastic anemia

Sickle cell anemia


Causes, incidence, and risk factors

While many parts of the body help make red blood cells, most of the work is done in the bone marrow. Bone marrow is the soft tissue in the center of bones that helps form blood cells.

Healthy red blood cells last between 90 and 120 days. Parts of your body then remove old blood cells. A hormone called erythropoietin made in your kidneys signals your bone marrow to make more red blood cells.

Hemoglobin is the oxygen-carrying protein inside red blood cells. It gives red blood cells their red color. People with anemia do not have enough hemoglobin.

Possible causes of anemia include:

Certain medications

Chronic diseases such as cancer, ulcerative colitis, or rheumatoid arthritis

Genetics: Some forms of anemia, such as thalassemia, can be inherited

Kidney failure

Blood loss (for example, from heavy menstrual periods or stomach ulcers)

Poor diet


Problems with bone marrow such as lymphoma, leukemia, or multiple myeloma

Problems with the immune system that cause the destruction of blood cells (hemolytic anemia)

Surgery to the stomach or intestines that reduces the absorption of iron, vitamin B12, or folic acid

Too little thyroid hormone (underactive thyroid, or hypothyroidism)

Testosterone deficiency


Possible symptoms include:

Chest pain

Dizziness or light-headedness (especially when standing up or with activity)

Fatigue or lack of energy


Problems concentrating

Shortness of breath (especially during exercise)

Some types of anemia may have other symptoms, such as:


Problems thinking


Signs and tests

The doctor will perform a physical examination, and may find:

Pale skin

Rapid heart rate

Heart murmur

Some types of anemia may cause other findings on a physical exam.

Blood tests used to diagnose some common types of anemia may include:

Blood levels of vitamin B12, folic acid, and other vitamins and minerals

Red blood count and hemoglobin level

Reticulocyte count

Ferritin level

Iron level

Other tests may be done to identify medical problems that can cause anemia.


Treatment should be directed at the cause of the anemia, and may include:

Blood transfusions

Corticosteroids or other medicines that suppress the immune system

Erythropoietin, a medicine that helps your bone marrow make more blood cells

Supplements of iron, vitamin B12, folic acid, or other vitamins and minerals

Expectations (prognosis)

The outlook depends on the cause.


Severe anemia can cause low oxygen levels in vital organs such as the heart, and can lead to a heart attack.

Calling your health care provider

Call your health provider if you have any symptoms of anemia, or any unusual bleeding.