Polycythemia vera (PV)
What is polycythemia vera?
Research‑backed patient education is central to MPN Research Foundation’s mission. People living with polycythemia vera (PV) and other myeloproliferative neoplasms (MPNs) deserve clear, accurate information they can trust to understand their diagnosis, symptoms, and treatment options.
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Understanding and diagnosing polycythemia vera (PV)
Blood flowing through your body contains several different kinds of cells. Red blood cells deliver oxygen to your tissues, white blood cells protect against infections, and platelets form clots to stop bleeding when needed. Your bones contain spongy tissue called bone marrow, where all these blood cells are created. The bone marrow functions like a factory, making the right amount of each blood cell type based on instructions from your genes.
Sometimes, the bone marrow factory receives the wrong instructions and starts making too many red blood cells. This is called polycythemia vera, or PV. It’s a type of blood cancer called a myeloproliferative neoplasm, or MPN. The name “polycythemia vera” tells us what’s happening. “Poly” means many and “cythemia” refers to blood cells. So, polycythemia means you have too many blood cells. “Vera” means true, meaning it is the primary problem, not caused by something else.
Red blood cells carry oxygen throughout your body. But when you have too many, the blood becomes thick and sticky, like honey instead of water. This thick blood doesn’t flow well through your blood vessels. It’s harder for oxygen to get where it’s needed.1
PV is most common in people over age 60, though it can happen at any age. Men are slightly more likely than women to develop PV. Polycythemia vera is rare. Just 1 or 2 people out of every 100,000 are diagnosed each year.²˒³
Serious complications from polycythemia vera
The thick blood caused by PV can form unwanted clots inside blood vessels. These can lead to heart attacks, strokes, or blockages in the legs. PV can also cause bleedingproblems. In addition, your spleenmay become enlarged as it works harder to filter the extra blood cells.¹˒²
What causes polycythemia vera?
PV happens because of changes in genes. The medical term for these types of changes is “mutations.” Almost all people with PV have a mutation in a gene called JAK2. The mutations signal the bone marrow to make too many red blood cells.²˒⁴
What are common polycythemia vera symptoms?
Many people with PV don’t feel sick at first. When PV does cause symptoms, they can include headaches, dizziness, redness of the face or hands, and itching, especially after a warm bath or shower.
Other symptoms can include blurred vision, ringing in the ears, feeling unusually tired, or having trouble concentrating. Others may experience night sweats.¹˒³
How is polycythemia vera diagnosed?
PV is often discovered during a routine blood test that shows high red blood cell counts or high hematocrit. Your regular doctor might notice this during a yearly checkup or when testing for another condition.²˒³
If your blood test shows high red blood cell counts, your doctor might refer you to a hematologist – a doctor specializing in blood disorders. They can run additional tests to determine what’s causing your high blood counts.²˒⁴
Before diagnosing PV, doctors need to rule out other reasons for high red blood cells. They will test for conditions including sleep apnea, lung diseases, heart problems, or problemsliving at high altitude.²˒⁴
Your hematologist will test your blood for gene mutations. They will look for the JAK2 mutation , which is present in more than 9 of every 10 people with PV. Finding this mutation helps confirm the PV diagnosis and gives doctors important information about your condition.²˒⁴
Doctors will measure your red blood cell count, hemoglobin and hematocritlevels. These testsshow how many red blood cells you have and how thick your blood has become. They will also check your level of erythropoietin, or EPO, a hormone that controls red blood cell production. In PV, this level is usually low.²˒⁴
Your doctor will take a small sample of bone marrow in a procedure called a bone marrow biopsy. This helps them see what is happening inside your bone marrow “factory,” and make sure it is really PV and not another condition.²˒⁴
Understanding your PV diagnosis and moving forward
Getting a PV diagnosis can feel overwhelming, but many people with PV live healthy lives with proper treatment. Your care team can guide you through what this diagnosis means for you.1,2 Once PV is diagnosed, your healthcare team will work with you to create a treatment plan that’s right for you.Understanding your condition is the first step towards managing it successfully and living well.⁴˒⁵
Managing and treating polycythemia vera (PV)
If you have polycythemia vera, or PV, getting treatment is vital. Treatment aims to reduce the risk of blood clots and bleeding, strokes, heart attacks, and keep blood counts in a safe range. Treatment also helps manage PV-related symptoms, prevent problems like deep vein or lung clots, and improve how you feel each day.¹˒²˒⁴
Blood clots are the most serious potential problem. About 2 to 3 in every 10 people with PV develops a clot.¹˒²
Risk levels when you have polycythemia vera
The type of treatment you receive for polycythemia vera depends on your risk level. Your risk is high if you are over 60 or had a previous blood clot. Your risk is low if you are under 60 and have never had a clot.²˒³ Your doctor will also look at factors such as high blood pressure, high cholesterol, and diabetes, since these can raise your risk for heart and blood vessel problems.2 Certain genetic changes in your blood cells may also affect PV over time.
Phlebotomy for polycythemia vera
Phlebotomy is often one of the first treatments for PV. It involves removing blood (much like a blood donation) to lower total red blood cells, thin the blood, and improve circulation. The goal is to keep the percentage of red cells in your blood (hematocrit) under 45%. This lowers the risk of a clot.¹˒²˒⁵
Low-dose aspirin for polycythemia vera
Some people with PV take low-dose aspirin each day. It helps keep small blood cells called platelets from clumping together and forming clots. This lowers the risk of heart attacks and strokes.¹˒²
Treatment for low-risk polycythemia vera patients
For low-risk patients, phlebotomypluslow-dose aspirin is often enough to keep the percentage of red cells in the blood below 45% and prevent problems.¹˒²˒³
Medicines for high-risk polycythemia vera patients
People with high-risk polycythemia vera often need medication in addition to low-dose aspirin. Medication reduces or slows the number of blood cells bone marrow makes. This reduces the risk of blood clots and helps control symptoms.²˒³˒⁵ You may still have phlebotomy, but medication will be the main treatment.
Hydroxyurea for polycythemia vera
Hydroxyurea is another medication for PV. It slows blood cell production in the bone marrow. Your doctor will adjust your dose based on your blood counts and how you respond.
Interferon therapy for polycythemia vera
Interferon is another treatment option for polycythemia vera. Given as a shot, it slows the production of blood cells in the bone marrow. The first interferon specifically for PV was approved by the FDA in 2021. You take interferon every 2 to 4 weeks.¹ Side effects can include feeling like you have the flu, headaches, muscle pain or mood changes.¹˒⁴
Ruxolitinib for polycythemia vera
Ruxolitinib is an FDA-approved option if hydroxyurea does not work or causes too many side effects. It blocks signals that tell the bone marrow to make too many blood cells. It helps control blood counts, shrink an enlarged spleen and manage other PV symptoms.¹˒²
Supportive care for polycythemia vera
Supportive care focuses on helping you feel your best. This means watching for blood clots, managing conditions like high blood pressure, high cholesterol and diabetes, and treating symptoms.²˒⁴ Working with your care team and going to appointments regularly helps you stay as healthy as possible.²˒³
Polycythemia vera changes over time
Over time, a small number of people with polycythemia vera (about 10 to 15 out of 100) may develop a related condition called post-PV myelofibrosis, where scar tissue builds up in the bone marrow.1,2 This change usually happens slowly, over many years.¹˒² In rare cases, PV can also progress to acute leukemia.¹˒² Regular checkups and tests help detect these changes early, so your care team can adjust treatment as needed.
Clinical trials and future options for polycythemia vera
New PV treatments are being studied in clinical trials. Researchers are discovering new ways to control blood counts, reduce symptoms, and improve the long-term outlook for people with PV. Talk to your doctor about whether a clinical trial might be right for you.
Team management and moving forward with polycythemia vera
Your care team works together to help manage PV. With the right treatment approach, most people with PV live well and reduce their risk of complications. Stay informed, keep all your appointments, and talk openly with your health care providers about your symptoms, side effects, and concerns. Working with your care team helps you take an active role in living well with PV.
Disclaimer: The information provided is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always consult your doctor about any questions you may have regarding a medical condition.
“Understanding and Diagnosing PV” references
MPN Research Foundation. What is polycythemia vera? https://mpnresearchfoundation.org/polycythemia-vera-pv
Tefferi A, Barbui T. Polycythemia vera: 2024 update on diagnosis, risk-stratification, and management. Am J Hematol. 2023 Sep;98(9):1465-1487.
Thapa B, Fazal S, Parsi M, Rogers HJ. Myeloproliferative Neoplasms. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–.
https://www.ncbi.nlm.nih.gov/books/NBK531464National Comprehensive Cancer Network (NCCN). NCCN Guidelines for Patients: Myeloproliferative neoplasms. Version 2024. https://www.nccn.org/patients/guidelines/content/PDF/mpn-patient.pdf
Khoury JD, Solary E, Abla O, et al. The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Myeloid and Histiocytic/Dendritic Neoplasms. Leukemia. 2022 Jul;36(7):1703-1719.
"Managing and Treating PV" references
MPN Research Foundation. Polycythemia Vera (PV).
https://mpnresearchfoundation.org/polycythemia-vera-pvTefferi A, Barbui T. Polycythemia vera: 2024 update on diagnosis, risk-stratification, and management. Am J Hematol. 2023 Sep;98(9):1465-1487.
National Comprehensive Cancer Network. NCCN Guidelines for Patients: Myeloproliferative Neoplasms. Version 2024.
https://www.nccn.org/patientresources/patient-resources/guidelines-for-patients/guidelines-for-patients-details?patientGuidelineId=27Lu X, Chang R. Polycythemia Vera. [Updated 2023 Apr 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.
https://www.ncbi.nlm.nih.gov/books/NBK557660National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Myeloproliferative Neoplasms. Version 2.2025.
https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1477
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