Key Points for This Section

Polycythemia vera is a disease in which too many red blood cells are made in the bone marrow. Possible signs of polycythemia vera include headaches and a feeling of fullness below the ribs on the left side. Special blood tests are used to diagnose polycythemia vera.

Polycythemia vera is a disease in which too many red blood cells are made in the bone marrow.

In polycythemia vera, the blood becomes thickened with too many red blood cells. The number of white blood cells and platelets may also increase. These extra blood cells may collect in the spleen and cause it to swell. The increased number of red blood cells or platelets in the blood can cause bleeding problems and make clots form in blood vessels. This can cause serious health problems such as stroke or heart attack. In patients older than 65 years, the risk of stroke and heart attack is higher, and polycythemia vera is more likely to become acute myeloid leukemia or chronic idiopathic myelofibrosis.

Possible signs of polycythemia vera include headaches and a feeling of fullness below the ribs on the left side.

Polycythemia vera often does not cause early symptoms. It is sometimes found during a routine blood test. Symptoms may occur as the number of blood cells increases. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• A feeling of pressure or fullness below the ribs on the left side.
• Headaches.
• Double vision or seeing dark or blind spots that come and go.
• Itching all over the body, especially after being in warm or hot water.
• Reddened face that looks like a blush or sunburn.
• Weakness.
• Dizziness.
• Weight loss for no known reason.

Special blood tests are used to diagnose polycythemia vera.

In addition to a complete blood count, other special blood tests are used to diagnose polycythemia vera. These tests include the following:

• Arterial blood gas (ABG) test: A test in which a sample of blood is taken from an artery to measure the amount of oxygen and carbon dioxide in the blood and the pH (acidity) of the blood.
• Serum erythropoietin test: A test in which a sample of blood is checked for the level of erythropoietin (a hormone that stimulates new red blood cells to be made).
• Leukocyte alkaline phosphatase (LAP) test: A test in which a sample of blood is checked to measure the amount of alkaline phosphatase (an enzyme) in leukocytes (white blood cells).

Glossary Terms

An aggressive (fast-growing) disease in which too many myeloblasts (immature white blood cells that are not lymphoblasts) are found in the bone marrow and blood. Also called acute myeloblastic leukemia, acute myelogenous leukemia, acute nonlymphocytic leukemia, AML, and ANLL.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

A tube through which the blood circulates in the body. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A progressive, chronic disease in which the bone marrow is replaced by fibrous tissue and blood is made in organs such as the liver and the spleen, instead of in the bone marrow. This disease is marked by an enlarged spleen and progressive anemia. Also called agnogenic myeloid metaplasia, idiopathic myelofibrosis, myelosclerosis with myeloid metaplasia, and primary myelofibrosis.

A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called blood cell count and CBC.

The process of identifying a disease, such as cancer, from its signs and symptoms.

A protein that speeds up chemical reactions in the body.

A substance that is naturally produced by the kidneys, and that stimulates the bone marrow to make red blood cells. When erythropoietin is made in the laboratory, it is called epoetin alfa or epoetin beta.

One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.

A type of immune cell. Most leukocytes are made in the bone marrow and are found in the blood and lymph tissue. Leukocytes help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are leukocytes. Also called WBC and white blood cell.

A tiny piece of a cell found in the blood that breaks off from a large cell found in the bone marrow. Platelets help wounds heal and prevent bleeding by forming blood clots. Also called thrombocyte.

A disease in which there are too many red blood cells in the bone marrow and blood, causing the blood to thicken. The number of white blood cells and platelets may also increase. The extra blood cells may collect in the spleen and cause it to become enlarged. They may also cause bleeding problems and make clots form in blood vessels.

A cell that carries oxygen to all parts of the body. Also called erythrocyte and RBC.

The clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.

An organ that is part of the lymphatic system. The spleen makes lymphocytes, filters the blood, stores blood cells, and destroys old blood cells. It is located on the left side of the abdomen near the stomach.

In medicine, a loss of blood flow to part of the brain, which damages brain tissue. Strokes are caused by blood clots and broken blood vessels in the brain. Symptoms include dizziness, numbness, weakness on one side of the body, and problems with talking, writing, or understanding language. The risk of stroke is increased by high blood pressure, older age, smoking, diabetes, high cholesterol, heart disease, atherosclerosis (a build-up of fatty material and plaque inside the coronary arteries), and a family history of stroke.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A type of immune cell. Most white blood cells are made in the bone marrow and are found in the blood and lymph tissue. White blood cells help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are white blood cells. Also called leukocyte and WBC.