Patient education: Thrombocytosis (The Basics)

What is thrombocytosis? — 

This is when the blood has too many "platelets." Platelets are blood cells that help blood to clot.

All blood cells, including platelets, are made in the center of the bones, in the "bone marrow."

What causes thrombocytosis? — 

There are 2 types of thrombocytosis:

●"Reactive" or "secondary" thrombocytosis – This is the most common type. It means thrombocytosis that is caused by another medical condition. Examples include low iron, blood loss, infection, inflammation, cancer, and certain medicines. It can also happen if the spleen has been removed or is not working well.

●"Autonomous or "primary" thrombocytosis – This is a problem with bone marrow or blood cells that leads to an increase in platelets. This is sometimes related to changes in certain genes.

Is there a test for thrombocytosis? — 

Yes. There is a test to check the number of platelets in the blood, called the "platelet count." This is often done as part of a "complete blood count," or "CBC."

The CBC also gives information about other blood cells. This can sometimes help the doctor figure out what is causing thrombocytosis.

If a blood test shows you have a high platelet count, your doctor will ask you about your symptoms and do an exam. They will also ask about past health problems, your medicines, and whether you smoke or drink alcohol. They will probably also order more tests, such as:

●A blood smear – This involves looking at blood cells under a microscope.

●Genetic testing

●Other blood tests

What are the symptoms of thrombocytosis? — 

Thrombocytosis does not always cause symptoms. People often find out they have it after a routine blood test.

When symptoms do happen, they depend on the type of thrombocytosis. For example, symptoms might include:

●Headache

●Dizziness

●Redness, warmth, or pain in the hands or feet

●Vision changes

●Abnormal bleeding, or blood clots

People sometimes also have symptoms related to the condition that caused thrombocytosis.

How is thrombocytosis treated? — 

It depends on the situation and the cause:

●If another health problem caused your thrombocytosis, you might need treatment for that problem. For example, if you have low iron levels, your doctor will give you extra iron. Often, platelet levels return to normal on their own.

●If you have blood clots, bleeding, or other serious problems, you might need treatment in the hospital.

●If you have a problem with your bone marrow or blood cells, treatment will depend on your situation. You might get medicine to decrease platelets in your blood. You might also need to take aspirin to help prevent blood clots.

Depending on your condition and test results, your doctor might refer you to a "hematologist." This is an expert in blood diseases.

More on this topic

Patient education: Platelet count (The Basics)
Patient education: Complete blood count (CBC) (The Basics)
Patient education: Polycythemia vera (The Basics)