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Primary polycythaemia (high red blood cells)

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Your blood is made of white blood cells, red blood cells, platelets, and plasmaPrimary polycythaemia, also called primary polycythaemia vera or PV, is caused by your bone marrow making too many red blood cells. Most people with polycythaemia remain well, but they have a higher risk of getting blood clots. These can lead to a deep vein thrombosis (DVT), pulmonary embolism, stroke or heart attack.

After many years, people with polycythaemia can sometimes develop other blood problems, such as anaemia, scarring of their bone marrow (a condition called myelofibrosis) or even leukaemia.

Primary polycythaemia is diagnosed with a blood test. You may also need a bone marrow biopsy.

Treatment to lower your red blood cells to the normal level reduces your risk of blood clots. This is either done by regularly removing blood (called bloodletting or venesection) or with medication.

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Written by Haematology Department, Christchurch Hospital. Adapted by HealthInfo clinical advisers. Last reviewed February 2023.


See also:

Understanding your complete blood count results

Page reference: 31421

Review key: HIPPO-31421