Tests and treatment for polycythaemia vera

The first test to diagnose polycythaemia vera (PV) is a blood test. This is to check:

  • the number of red blood cells
  • the haematocrit level
  • the number of platelets

The haematocrit level is the amount of space the red blood cells take up in the blood. When there are more red blood cells they take up more space and so the haematocrit level is higher.

Some people with PV have an increase in the number of platelets. And some people may have an increased number of white blood cells.

If the first blood test suggests you have PV, you might have another blood test to look for a change in a gene Open a glossary item called JAK2. The JAK2 gene makes a protein that controls how many blood cells the stem cells make. A fault with your JAK2 gene means the stem cells can start producing red blood cells when they're not meant to.

Doctors are learning more about genetic changes all the time. You might have tests for other gene changes.

Other tests

Other tests you might have include:

  • a bone marrow test
  • a chest x-ray
  • a blood test to measure the level of a blood cell growth factor called erythropoietin (EPO)
  • an ultrasound scan of your tummy (abdomen) to check the size of your spleen
  • blood tests to check how well your liver and kidneys are working
  • a test to measure the oxygen level in your blood (pulse oximetry)

We have more information about some of these tests on our tests and scans page.

Treatment for PV

Treatment for PV aims to reduce the number of red blood cells. This helps to control your symptoms and to prevent any more serious problems. The treatment you need will depend on your risk of more serious problems, such as blood clots. You might have more than one of these treatments.

The treatment you have is individual. Your team will decide if you are at low risk, intermediate risk or higher risk, of developing a blood clot. This helps your team decide the best treatment for you.

Doctors use a number of factors to work out if your risk, these include if you:

  • have had blood clots before
  • smoke
  • have high blood pressure
  • have diabetes

People who tend to be high risk are also over 60 years old.

Treatment if you are at low or intermediate risk for blood clots


This is a simple procedure that involves taking your blood. It is sometimes called phlebotomy. Your nurse removes around a pint of blood (350- 450ml). This reduces the number of red cells in your blood. It might need to be done once a week to begin with. Then it can be repeated as often as you need it.

Low dose aspirin

PV can raise the number of platelets in your blood. This can cause problems with blood clots. Low dose aspirin can lower your risk of getting a blood clot. You take it as a tablet.

Treatment if you are at high risk for blood clots


This treatment uses cell killing (cytotoxic) drugs to destroy the immature blood cells. The drugs work by disrupting the growth of cells and stopping them from dividing. It helps to lower the number of red blood cells and platelets. There is a small increase in the risk of developing a leukaemia if you have this treatment repeatedly over a long time.

It’s likely you will have the chemotherapy drug hydroxycarbamide. Hydroxycarbamide comes as capsules.

If hydroxycarbamide is not working

Peginterferon alfa 2a

This is a targeted treatment that helps to reduce the rate at which blood cells are made. It can help with the symptoms of PV, especially itching. Peginterferon alfa 2a is given as an injection. Side effects include flu like symptoms and tiredness.

Other treatments


You might have a chemotherapy drug called busulfan. You might have this if you are allergic to hydroxycarbamide. Or you might have it if hydroxycarbamide is not working for you.


When red blood cells are broken down by the body, they produce uric acid. If you have too much uric acid in your blood, it can collect in the joints and cause painful swelling, called gout. Allopurinol lowers the amount of uric acid in the blood and so helps to reduce the symptoms of gout.

Radioactive phosphorus

Radioactive phosphorus (P-32) is a type of internal radiotherapy.

Your bone marrow absorbs the radioactive phosphorus and gets a dose of radiation. The radiation slows down the number of red blood cells and platelets made. Very little radiation goes to the rest of the body.

Aspirin and venesection for people at high risk of blood clots

Alongside the treatments listed above you might have:

  • low dose aspirin to lower the risk of blood clots
  • venesection to reduce the number of red cells in the blood

Extra support

You might need extra treatment or support from your specialist team sometimes, such as:

  • during pregnancy or childbirth
  • if you are having an operation

Healthy lifestyle

Your healthcare team might discuss ways to maintain a healthy lifestyle and help with stopping smoking if you need it.

We have information on healthy diet and lifestyle on our causes of cancer and reducing your risk pages.

Support and coping

We have information on support organisations that can help you cope with the diagnosis and treatment of polycythaemia vera.

  • Management of polycythaemia vera: a critical review of current data

    MF McMullin, BS Wilkins and CN Harrison

    British Journal of Haematology, 2016. Volume 172, Issue 3

  • Polycythaemia/erythrocytosis

    National Institute for Health and Care Excellence (NICE) Clinical Knowledge Summary, January 2018

  • Wintrobe’s Atlas of Clinical Hematology, 2nd edition

    BB Weksler, GP Schechter and S Ely

    Wolters Kluwer, 2018

  • Polycythaemia Vera

    BMJ Best Practice, Accessed April 2020

  • British National Formulary

    Accessed April 2020

  • Electronic Medicine Compendium

    Accessed April 2020

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in.

Last reviewed: 
07 May 2020
Next review due: 
07 May 2023

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