Because polycythemia vera (PV) is a rare type of blood cancer, a diagnosis often comes as a result of seeing your doctor for other reasons.

To diagnose polycythemia vera (PV), your doctor will do a physical examination, blood test, and may perform a bone marrow biopsy. 

Physical Exam

A diagnosis of PV is usually not the result of a physical exam, but your doctor may observe symptoms of the disease during a routine visit. 

Some physical symptoms your doctor may recognize are bleeding gums and a reddish hue to your skin. If you have symptoms or your doctor suspects PV, they will most likely examine and palpate your spleen to determine if it is enlarged.

Blood Tests

There are three main blood tests that are used to diagnose PV.

Complete Blood Count (CBC)

A CBC measures the number of red and white blood cells and platelets in your blood. It will also tell your doctor what your hemoglobin level is in your red blood cells. Hemoglobin is a protein rich in iron that helps red blood cells carry oxygen from the lungs to the rest of the body. If you have PV, your hemoglobin level will be elevated.

A CBC will also measure your hematocrit. Hematocrit is the volume of your blood that is made up of red blood cells. If you have PV, you will have a high hematocrit percentage.

Blood Smear

This is a blood sample that can show if your red blood cell count is higher than normal. It can also detect abnormal blood cells linked to myelofibrosis, which is serious bone marrow scarring that occurs when PV is in its most advanced stage.

Erythropoietin Test

Using a blood sample, this test measures the amount of the hormone erythropoietin (EPO) in your blood. EPO is made by the cells in your kidney and signals stem cells in the bone marrow to make more red blood cells. If you have PV, your EPO level will be low. This is because your blood cell production is being driven not by this hormone, but by a JAK2 gene mutation.

Bone Marrow Tests

Bone marrow tests can determine if your bone marrow is making normal amounts of blood cells. If you have PV, your bone marrow is making too many blood cells and the signal to make them doesn’t turn off.

There are two main types of bone marrow tests:

  • bone marrow aspiration
  • bone marrow biopsy

During a bone marrow aspiration, a small amount of fluid is removed from your bone marrow with a needle. During a bone marrow biopsy, a small amount of the solid part of your bone marrow is removed with a needle.

These bone marrow samples are sent to a lab for analysis by either a hematologist or a pathologist. These specialists will analyze the biopsies and send your primary doctor the results within a few days.  

JAK2 Gene

Knowing that you have PV is difficult, but the discovery of the JAK2 gene and its mutation JAK2 V617A in 2005 was a major breakthrough in learning about and diagnosing PV. 

About 95 percent of people with PV have this genetic mutation. Experts agree that it is likely that those who don’t have the mutation may be at early stages in the progression of the disease.

The genetic abnormality can be detected in both your blood and your bone marrow, requiring either a blood sample or a bone marrow sample.

Because of the discovery of the JAK2 gene mutation, those who are well versed in this disease can more easily determine when you have it. It simply requires a CBC and a genetic test.

Although PV is rare, getting routine blood tests is one of the best preventive measures in diagnosing it and getting treatment. If it’s determined that you do have PV, there are various methods of managing the disease depending upon your age and at what stage it’s discovered.