What Is a Normal Platelet Count?

A normal platelet count is between 150,000 to 450,000 per microliter (mcL) of blood. This range is generally applicable to all adults. However, research has suggested that normal platelet counts might be a little different in men and women. Age might also affect what is considered a normal platelet count because these cells tend to decrease over time.

Having a normal platelet count is important: Your bone marrow produces platelet cells so your body can form clots to prevent bleeding and seal blood vessels if they are damaged.

Having platelet counts that are out of the normal range can be a sign of health condition or a side effect of a medication you're on.

This article covers normal platelet count ranges, as well as abnormal ones. You will also learn what causes platelets to go out of the normal range, as well as how these conditions can be treated.

Normal Platelet Counts

A platelet count between 150,000 to 450,000/mcL of blood is considered normal. However, this might vary a bit depending on certain factors.

Research has shown that platelet counts are related to genetics, ethnicity, and age.

For example, studies have found that the range of normal platelet counts between men and women is a little different after age 15:

• For women, a normal platelet count is between 157,000 and 371,000/mcL of blood
• For men, a normal platelet count is between 135,000 and 317,000/mcL of blood

Platelet counts are also generally stay stable until after age 60, when they start to decrease.

Healthcare providers do not necessarily use different normal platelet ranges based on such factors, but they may be taken into some consideration.

Higher-Than-Normal Platelet Count

A platelet count over 450,000/mcL is called thrombocytosis.

A higher-than-normal platelet count can cause blood clots to form and lead to a condition called acquired von Willebrand disease.

In this disease, the platelets fail to interact properly with the blood vessel wall at sites of injury. The failure to seal the site of injury leads to bleeding.

There are two types of thrombocytosis:

• In primary thrombocytosis, there is a natural abnormality (such as a genetic mutation) in the bone marrow cells that produce platelets. That means too many platelets are being made all the time.
• In secondary thrombocytosis, there is no problem with the cells producing platelets. They are making too many platelets as a normal response to signals that they are getting from another process going on in the body (such as inflammation).

Some possible causes of high platelets include:

• Infection
• Iron deficiency anemia
• Hemolytic anemia
• Inflammatory bowel disease
• Certain types of cancer
• Tuberculosis

The symptoms of thrombocytosis may include abnormal bruising or bleeding and stroke-like symptoms. However, many people who have a high platelet count do not have symptoms at all.

Lower-Than-Normal Platelet Count

A platelet level of less than 150,000/mcL is considered low. This is called thrombocytopenia.

When a blood vessel becomes damaged, platelets are activated to stick together and form a clot to seal the blood vessel wall to stop or prevent bleeding.

When your platelet level is below normal, you are risk for more-than-typical blood loss with something as simple as a cut from shaving or injury from a sport. In severe cases, internal and external bleeding can be significant.

Low platelets can be caused by:

• Bone marrow dysfunction: If the bone marrow is not functioning, it may not be making enough platelets.
• Enlarged spleen: Platelets can sit in an enlarged spleen instead of being circulated out into the blood vessels.
• Liver disease: Diseases that affect the liver can lead to platelet dysfunction and spleen enlargement.
• Immune system destruction: Sometimes, the immune system mistakes platelets as foreign and destroys them. 
• Medications: Being on chemotherapy or taking antibiotics, seizure medication, and blood thinners can affect platelet levels.

Symptoms of thrombocytopenia may include:

• Bleeding (e.g., from the gums when brushing teeth or in the stool)
• Heavy menstrual periods
• Bruising
• Petechiae (small red pinpoint spots of bleeding that may look like a rash)

Is Your Platelet Count Normal?

You can find out if your platelet count is normal by having a blood test called a complete blood count (CBC). A healthcare provider may order this test as part of a routine physical exam or if they are exploring the possibility of a health condition.

Blood will be drawn and then sent to a lab, where it will go into a machine that counts all the different types of cells in your blood.

Results will reveal not only the number of each you have, but the size of the cells as well.

The size of platelets is referred to as the mean platelet volume (MPV). Like your platelet count, this information can be useful in helping identify a health concern.

If the MPV is higher than normal, it means the platelets are larger than normal. An elevated MPV can be caused by:

• Heart disease
• Artificial heart valves
• Diabetes
• Thrombocytopenia (low platelets)
• Myeloproliferative diseases
• Liver disease
• Severe infection

A low MPV means the platelets are smaller than normal. A decreased MPV can be caused by:

• Infections (e.g. HIV)
• Iron-deficiency anemia
• Bone marrow disorders
• Kidney disease
• Chemotherapy
  

Summary

Platelets are cells made by the bone marrow that help clot your blood. A normal platelet count is necessary for the body to repair itself and prevent bleeding if blood vessels get damaged.

If your body is making too many platelets or too few platelets, it can lead to health problems. Having abnormally high platelet counts or low platelet counts can also be a sign of diseases and conditions.

You can find out if your platelet count is normal by having a blood test. Your provider can let you know what your results mean and if you need treatment.