Diagnosis of Polycythemia Vera

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Polycythemia vera is not hereditary, so you wouldn’t necessarily know to self-check or monitor for polycythemia vera until you have already been diagnosed.

After diagnosis, it is important that you monitor the effects of your condition so you will be able to quickly recognize complications or signs that it could be worsening. 

Polycythemia vera is diagnosed based on blood tests

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Self-Checks/At-Home Testing

You should regularly check for signs of progression or complications if you have polycythemia vera. It will also be beneficial if the people who you live with are familiar with the complications, as well, so they can call for emergency help if you need it. 

Symptoms to regularly check for include: 

  • Itchy skin
  • Redness of your skin 
  • Increasing fatigue
  • Dizziness 
  • Bruising 
  • Prolonged bleeding
  • Worsening fatigue 
  • Weight loss
  • Blood in your stool or black appearing stools 
  • Enlarging appearance of your abdomen 
  • A feeling of abdominal fullness

You should talk to your doctor if you develop any of these problems. Many of them can be treated symptomatically. And sometimes these are indicators that you need treatment for your polycythemia vera. 

Serious symptoms to look out for when you have polycythemia vera include: 

  • Difficulty breathing
  • Severe headaches
  • Severe abdominal pain 
  • Weakness on one side of the body 
  • Vision changes 
  • Chest pain 
  • Seizures

Get immediate medical attention if you develop these problems. They can worsen rapidly, and they do require prompt medical management. 

Physical Examination 

Polycythemia vera can cause some physical signs that your doctor may detect with a physical examination. These typically develop at late stages of the disease, and they are usually part of monitoring the disease rather than diagnosis. However, they can occur early, during the initial diagnostic process, as well. 

Signs of polycythemia vera include:

  • Splenomegaly (enlarged spleen), which can cause a large, full abdomen 
  • Bleeding gums 
  • Bruising on the body 
  • Red skin 

Your doctor will periodically check for these signs at your regular appointments. 

Labs and Tests

The laboratory evaluation is the most definitive diagnostic assessment of polycythemia vera. Blood tests will show abnormalities in certain red blood cell levels, and this can be the first indication that you might have polycythemia vera.

Often, the blood test that prompts a diagnosis of polycythemia vera is done for another reason, like as part of a routine yearly physical. 

If your blood tests are consistent with polycythemia vera, you might also have a genetic test as part of the diagnosis. 

Complete Blood Count (CBC)

A complete blood count (CBC) is a routine blood test that you may have as part of your regular checkups or if you have an infection or another medical problem. This test includes several measurements of red blood cells and white blood cells. Polycythemia vera is often diagnosed based on a routine CBC.

Hemoglobin is the protein in red blood cells that carries oxygen. Hematocrit is a reflection of the volume of red blood cells in your blood. These measures are abnormal in polycythemia vera.

The World Health Organization's (WHO) diagnostic criteria for polycythemia vera are:

  • Hemogobin greater than 16.5 grams/deciliter (g/dl) in men or greater than 16.0 g/dL in women (normal is 13.2–16.6 g/dL for men and 11.6–15 grams/dL for women); or hematocrit greater than 49% for men (normal is 38.3%–48.6%) or greater than 48% for women (normal is 35.5%–44.9%) or increased red blood cell mass.
  • Janus kinase 2 genetic mutation: This is a genetic abnormality that is present in 98% of people who have polycythemia vera. It is not hereditary, and the cause of the abnormality is not known. It is detected with a specially requested genetic blood test.
  • Bone marrow shows trilineage proliferation with pleomorphic (varying in size and shape) mature megakaryocytes (the cells that produce platelets). "Trilineage" means that the cells can produce red blood cells, some types of white blood cells, and platelets.
  • Erythropoietin: This hormone stimulates the production of red blood cells. Erythropoietin is low in polycythemia vera. This is a minor criterion.

Other Tests and Complications

Sometimes other tests can be abnormal if you have polycythemia vera or complications of polycythemia vera. 

Some possible tests can include:

  • Polycythemia vera may cause high white blood cell counts or high platelet counts, especially at late stages. These abnormalities would be detected with a CBC, and there are no specific criteria because they are not always abnormal. Also, abnormalities are not diagnostic of the condition.
  • A blood smear is a microscopic examination of a small blood sample. If you have polycythemia vera, this test may show a higher-than-normal number of red blood cells. 
  • Bone marrow biopsy is a procedure in which bone marrow cells are extracted with a needle. It is safe, but it can be uncomfortable. The cells are examined in the lab and may show signs consistent with myelofibrosis (bone marrow scarring and cancer) or acute myeloid leukemia (a type of white blood cell cancer), which are complications of polycythemia vera. 


Imaging tests are not routinely part of the diagnosis of polycythemia vera, but you may need imaging tests if you have complications, such as blood clots or bleeding. 

Examples of imaging tests you might have include:

  • Brain magnetic resonance imaging (MRI): You might have an MRI of your brain if you have symptoms of a stroke.
  • Abdominal CT (computed tomography) scan: You might have this test if you have symptoms of splenomegaly (enlarged spleen). 
  • Bone scan: You might have this test if you have bone pain. 

There are a variety of other imaging tests you may need, depending on the type of complications you might be developing. 

Differential Diagnosis 

There are a few conditions besides polycythemia vera that could cause high hemoglobin and hematocrit levels.

Your doctor may consider these other potential causes of your symptoms as you are being evaluated for polycythemia vera:

  • Smoking 
  • Chronic lung disease 
  • Sleep apnea (breathing repeatedly stops and starts while sleeping)
  • Dehydration (loss of too much fluid)
  • Cancer 

Generally, your other symptoms, medical history, and physical examination will help point to the cause of your high red blood cell count, but you can have testing to distinguish these causes, if necessary. For example, erythropoietin is low in polycythemia vera and it is high in some other conditions that cause high red blood cell counts, including smoking and sleep apnea.


The diagnosis of polycythemia vera is based on blood tests. Since the condition doesn’t usually cause symptoms at early stages, it might be detected on a blood test that was ordered for another reason. If you have been diagnosed with polycythemia vera, you may need periodic testing to assess for potential complications so you can get the right medical treatment at the right time.

A Word From Verywell

A diagnosis of polycythemia vera can be unexpected, especially if found incidentally. Be sure to note the questions you have about it and discuss them thoroughly with your healthcare professional. Ask what you can expect for monitoring for progression of the condition and its complications.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Tefferi A, Barbui T. Polycythemia vera and essential thrombocythemia: 2019 update on diagnosis, risk-stratification and management. Am J Hematol. 2019 Jan;94(1):133-143. doi:10.1002/ajh.25303

  3. Iurlo A, Cattaneo D, Bucelli C, Baldini L. New perspectives on polycythemia vera: From diagnosis to therapy. Int J Mol Sci. 2020 Aug 13;21(16):5805. doi:10.3390/ijms21165805

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By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.