How Is Polycythemia Vera Diagnosed?

Polycythemia vera (PV) may not cause signs or symptoms for years. Thus, the disease often is found during routine blood tests done for other reasons. If the results of your blood tests aren't normal, your doctor may want to do more tests.

Your doctor will diagnose PV based on your signs and symptoms, your age and overall health, your medical history, a physical exam, and the results from tests.

During the physical exam, your doctor will look for signs of PV. He or she will check for an enlarged spleen, red skin on your face, and bleeding from your gums.

If your doctor confirms that you have polycythemia, the next step is to find out whether you have primary polycythemia (polycythemia vera) or secondary polycythemia.

Your medical history and physical exam may confirm which type of polycythemia you have. If not, you may have tests that check the level of the hormone erythropoietin (EPO) in your blood.

People who have PV have very low levels of EPO. People who have secondary polycythemia usually have normal or high levels of EPO.

Specialists Involved

If your primary care doctor thinks you have PV, he or she may refer you to a hematologist. This is a doctor who specializes in diagnosing and treating blood diseases and conditions.

Diagnostic Tests

You may have a number of different blood tests to diagnose PV. These tests include a complete blood count (CBC) and other tests, if necessary.

Complete Blood Count

Often, the first test used to diagnose PV is a CBC. The CBC measures many different parts of your blood.

This test checks your hemoglobin (HEE-muh-glow-bin) and hematocrit (hee-MAT-oh-crit) levels. Hemoglobin is the iron-rich protein in red blood cells that carries oxygen to the body. Hematocrit is a measure of how much space red blood cells take up in your blood. A high level of hemoglobin or hematocrit may be a sign of PV.

The CBC also checks the number of red blood cells, white blood cells, and platelets in your blood. Abnormal results may be a sign of PV, a blood disorder, an infection, or another condition.

Other Blood Tests

Blood smear. For this test, a small sample of blood is drawn from a vein, usually in your arm. The sample of blood is put on a glass slide. A microscope is then used to look at your red blood cells.

A blood smear can show whether you have a higher-than-normal number of red blood cells. The test also can show abnormal types of blood cells that are linked to myelofibrosis and other conditions related to PV.

Erythropoietin level. This blood test measures the level of EPO in your blood. EPO is a hormone that stimulates bone marrow to make new blood cells. People who have PV have very low levels of EPO. People who have secondary polycythemia usually have normal or high levels of EPO.

Bone Marrow Tests

Bone marrow tests are used to check whether your bone marrow is healthy. These tests also show whether your bone marrow is making normal amounts of blood cells.

If the tests show that your bone marrow is making too many blood cells, it may be a sign that you have PV.