A blood test called a complete blood count (CBC) can show if your platelet count is too high. You may also need blood tests to check for:

  • High or low iron levels.
  • Markers of inflammation.
  • Undiagnosed cancer.
  • Gene mutations.

You might also need a procedure that uses a needle to remove a small sample of your bone marrow for testing.


Reactive thrombocytosis

Treatment for this condition depends on the cause.

  • Blood loss. If you've had significant blood loss from a recent surgery or an injury, your elevated platelet count might resolve on its own.
  • Infection or inflammation. If you have a chronic infection or an inflammatory disease, your platelet count likely will remain high until the condition is under control. In most cases, your platelet count will return to normal after the cause is resolved.
  • Spleen removed. If you've had your spleen removed, you might have lifelong thrombocytosis, but you're unlikely to need treatment.

Essential thrombocythemia

People with this condition who have no signs or symptoms usually don't need treatment. You might need to take daily, low-dose aspirin to help thin your blood if you're at risk of blood clots. Don't take aspirin without checking with your health care team.

You might need to take prescription medicine or have procedures to lower your platelet counts if you:

  • Have a history of blood clots and bleeding.
  • Have risk factors for heart disease.
  • Are older than 60.
  • Have a very high platelet count.

Your doctor might prescribe platelet-lowering drugs such as hydroxyurea (Droxia, Hydrea), anagrelide (Agrylin) or interferon alfa (Intron A).

In emergencies, platelets can be filtered from your blood with a machine. This procedure is called plateletpheresis. The effects are only temporary.

Preparing for your appointment

It's likely that a routine blood test showing a high platelet count will be your first indication that you have thrombocytosis.

Besides taking your medical history, examining you physically and running tests, your doctor might ask about factors that could affect your platelets, such as a recent surgery, a blood transfusion or an infection. You might be referred to a hematologist, which is a doctor who specializes in blood diseases.

Here's some information to help you get ready for your appointment.

What you can do

Be aware of pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet.

Make a list of:

  • Your symptoms and when they began.
  • Your medical history, including recent infections, surgical procedures, bleeding and anemia.
  • All medications, vitamins and other supplements you take, including doses.
  • Questions to ask your doctor.

Take a family member or friend along, if possible, to help you remember the information you're given.

For thrombocytosis, questions to ask include:

  • What tests do I need?
  • Is my condition likely temporary or chronic?
  • What treatment do you recommend?
  • What follow-up care will I need?
  • Do I need to restrict my activity?
  • I have other health conditions. How can I best manage them together?
  • Should I see a specialist?
  • Do you have brochures or other printed material that I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your doctor is likely to ask you questions, such as:

  • Have your signs and symptoms worsened over time?
  • Do you drink alcohol? Do you smoke?
  • Have you had your spleen removed?
  • Do you have a history of bleeding or a lack of iron?
  • Do you have a family history of high platelet counts?
Dec. 30, 2022

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  1. Platelet disorders: Thrombocythemia and thrombocytosis. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health/thrombocythemia-thrombocytosis. Accessed Nov. 30, 2022.
  2. Ferri FF. Thrombocytosis. In: Ferri's Clinical Advisor 2023. Elsevier; 2023. https://www.clinicalkey.com. Accessed Nov. 30, 2022.
  3. Tefferi A. Approach to the patient with thrombocytosis. https://www.uptodate.com/contents/search. Accessed Nov. 30, 2022.
  4. Reactive thrombocytosis (Secondary thrombocythemia). Merck Manual Professional Version. https://www.merckmanuals.com/professional/hematology-and-oncology/myeloproliferative-disorders/reactive-thrombocytosis-secondary-thrombocythemia?query=thrombocytosis. Accessed Nov. 30, 2022.
  5. Tefferi A. Diagnosis and clinical manifestations of essential thrombocythemia. https://www.uptodate.com/contents/search. Accessed Nov. 30, 2022.
  6. Essential thrombocythemia. Merck Manual Professional Version. https://www.merckmanuals.com/professional/hematology-and-oncology/myeloproliferative-disorders/essential-thrombocythemia?query=thrombocytosis. Accessed Nov. 30, 2022.
  7. Kaushansky K, et al., eds. Hereditary and reactive thrombocytosis. In: Williams Hematology. 10th ed. McGraw Hill; 2021. https://accessmedicine.mhmedical.com. Accessed Nov. 30, 2022.
  8. Tefferi A. Prognosis and treatment of essential thrombocythemia. https://www.uptodate.com/contents/search. Accessed Nov. 30, 2022.
  9. Pruthi RK (expert opinion). Mayo Clinic. Dec. 7, 2022.


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