During an exam for a routine physical or another condition, your doctor might find that your spleen is enlarged or you have signs or symptoms of an infection or another condition. In that case, your doctor might order a complete blood count. This test can determine whether your platelet count is higher than normal.

Because a number of conditions can cause a temporary rise in your platelet count, your doctor likely will repeat the blood test to see if your platelet count remains high over time.

Your doctor might also order tests to check for:

  • Abnormal levels of iron in your blood
  • Markers of inflammation
  • Undiagnosed cancer
  • Associated 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.

  • If you've had significant blood loss from a recent surgery or an injury, your elevated platelet count might resolve on its own.
  • 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.
  • If you've had your spleen removed (splenectomy), you might have lifelong thrombocytosis, but you're unlikely to need treatment.

Essential thrombocythemia

People with this condition who have no signs or symptoms are unlikely to need treatment as long as the condition is stable. Your doctor might recommend that you 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 doctor.

You might need to take drugs 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 platelet count greater than 1 million

Your doctor might prescribe platelet-lowering drugs primarily in the form of hydroxyurea (Droxia, Hydrea) or interferon alfa (Intron A).

Platelets can be removed from your blood by a procedure that’s similar to dialysis. A needle connected to a tube is placed in a vein and your blood is fed through a machine that filters out platelets. Then the filtered blood is returned to your body through an intravenous (IV) line. This procedure is used only in emergencies, such as if essential thrombocythemia has caused a stroke.

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 doctor who specializes in blood diseases (hematologist).

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?

Thrombocytosis care at Mayo Clinic

Oct. 27, 2020
  1. Tefferi A. Approach to the patient with thrombocytosis. https://www.uptodate.com/contents/search. Accessed July 31, 2018.
  2. Thrombocythemia and thrombocytosis. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/thrombocythemia-and-thrombocytosis. Accessed July 31, 2018.
  3. AskMayoExpert. Essential thrombocythemia (adult). Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2017.
  4. Reactive thrombocytosis (secondary thrombocythemia). Merck Manual Professional Version. http://www.merckmanuals.com/professional/hematology-and-oncology/myeloproliferative-disorders/reactive-thrombocytosis-secondary-thrombocythemia. Accessed July 31, 2018.
  5. Tefferi A. Diagnosis and clinical manifestations of essential thrombocythemia. https://www.uptodate.com/contents/search. Accessed July 31, 2018.
  6. Morrow ES. Allscripts EPSi. Mayo Clinic, Rochester, Minn. April 2, 2018.


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