What is Polycythemia Vera?

What is Polycythemia Vera?

Polycythemia vera is a disease in which too many red blood cells are made in the bone marrow. In polycythemia vera, or PV, 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, white blood cells, or platelets in the blood can cause bleeding problems and make clots form in blood vessels. This can increase the risk of stroke or heart attack. In people who are older than 65 years or who have a history of blood clots, the risk of stroke or heart attack is higher. People with polycythemia vera also have an increased risk of acute myeloid leukemia or primary myelofibrosis.


Polycythemia vera often does not cause early signs or symptoms. It may be found during a routine blood test. Signs and symptoms may occur as the number of blood cells increases. Symptoms of PV include headaches and a feeling of fullness below the ribs on the left side. Other conditions may cause the same signs and symptoms. Check with your doctor if you have any of the following:

  • 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, bone marrow aspiration and biopsy, and cytogenetic analysis, a serum erythropoietin test is used to diagnose PV. In this test, a sample of blood is checked for the level of erythropoietin (a hormone that stimulates new red blood cells to be made). In PV, the erythropoietin level would be lower than normal because the body does not need to make more red blood cells.

Source: National Cancer Institute, cancer.gov

Looking for more information on PV?

These websites are a good start:


Cancer Support Community  

Leukemia & Lymphoma Society

MPN Advocacy & Education International

MPN Education Foundation 

MPN Research Foundation 

The MDS Foundation

National Cancer Institute 

This article was published in Coping® with Cancer magazine, May/June 2019.