What Does It Mean If Your Platelet Count Is High?

Medically Reviewed on 12/7/2022
High Platelet Count
A high platelet count is considered as over 450,000 platelets per microliter of blood.

When platelets are high, clots form more easily in the blood vessels, reducing blood flow. The decreased blood flow results in various complications, such as stroke and pulmonary embolism.

Platelets or thrombocytes are blood cells that are formed in the bone marrow. These cells help form blood clots and stop bleeding. The normal platelet count ranges from 150,000 to 450,000 per microliter of blood.

Major functions of platelets include:

  • Hemostasis
  • Thrombosis
  • Wound healing

What are the specific factors that affect platelet count?

Thrombocytosis is a condition in which there is an elevated platelet count. The two main types of thrombocytosis include:

  1. Essential thrombocythemia
  2. Reactive thrombocytosis
Table 1. Normal elevated and decreased platelet count
High platelet count More than 450,000 per microliter of blood
Normal platelet count 150,000 to 450,000 per microliter of blood
Low platelet counts Less than 150,000 per microliter of blood

What is essential thrombocythemia?

Essential thrombocythemia is a rare blood disorder that produces excessive platelets. Increased platelet count results in thrombus formation in the blood vessel, which causes severe complications, such as stroke and pulmonary embolism.

People with essential thrombocythemia have normal life expectancy if monitored and treated properly. Essential thrombocythemia is the most common form of myeloproliferative disorder.

  • Essential thrombocythemia occurs mostly in people older than 60 years.
  • Women who have given birth to female children are at a higher risk than those who have given birth to male children.

Myeloproliferative disorders are rare blood cancers that are caused by mutations in stem cells in the bone marrow. The mutations cause excess production of any combination of white blood cells, red blood cells, and platelets.

Causes of essential thrombocythemia

Essential thrombocythemia is caused by the genetic mutation in Janus kinase 2. The other gene mutations that result in essential thrombocythemia are CALR and MPL genes.

This gene mutation results in the overproduction of red blood cells and increases the viscosity of the blood. The thickened blood may result in decreased blood flow, thus preventing the required amount of oxygen from reaching the organs. The overproduction of cells may also result in abnormal blood clots.

What is reactive thrombocytosis?

Reactive thrombocytosis is also known as secondary thrombocytosis. In this condition, the increased platelet count is due to a response to some factors, such as injury, infection, any surgical procedure, and the absence of the spleen. The body reacts to these underlying factors, which results in elevated platelet count. Usually, reactive thrombocytosis is temporary.

Causes of reactive thrombocytosis

Various factors result in reactive thrombocytosis. A few causes of reactive thrombocytosis include:


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What are the symptoms of increased platelet count?

The following are the symptoms of an increased platelet count:

Severe complications include:

  • Excess bleeding 
  • Formation of unusual blood clots in the abdomen, called Budd–Chari syndrome, which increases the risk of stroke and heart attacks

Few people with thrombocythemia may also develop erythromelalgia, a condition that results in pain, swelling, redness, tingling, and numbness in the hands and feet.

How to detect increased platelet count

The following tests help identify the increased platelet count and determine the causes of increased platelet count:

How to treat increased platelet count

If thrombocytosis does not cause any symptoms, no treatment is required; however, the individual may require routine checkups.

If required, your healthcare provider may advise a few treatment options, such as:

  • Taking daily low-dose aspirin to prevent blood clots
  • Taking medicines that suppress the platelet production in bone marrow, such as hydroxyurea and anagrelide

Sometimes, splenectomy is required to reduce the platelet reduction. It is commonly recommended to reduce the risk of platelet destruction.

Medically Reviewed on 12/7/2022
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