A high red blood cell count is generally considered to be anything above 6.1 million red blood cells for males, 5.4 million for females, and 5.5 for children. Additional tests will help your healthcare provider determine the cause of your high red blood cell count and next steps in your care.
A high red blood cell count means the number of red blood cells in your bloodstream is higher than normal. Red blood cells are one of the major components of your blood, along with white blood cells and platelets. Red blood cells help carry oxygen throughout your body. But, when your red blood cell count is high, it could mean you have an underlying health condition.
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Healthcare providers measure your red blood cell count to diagnose medical conditions and learn more about your health. What’s considered normal may vary depending on where you’re tested. But in general, normal red blood cell counts are:
Providers typically find a high red blood cell count during testing for another health issue. You may need more tests to determine what’s causing the higher levels. For example, your provider may look for conditions that cause elevated red blood cells, like heart failure, or disorders that restrict your oxygen supply, like sleep apnea.
If you have a high red blood cell count, then you have something called erythrocytosis. This makes your blood thicker than it should be, and it could increase your risk for blood clots.
Your healthcare provider can run a number of tests to determine how many red blood cells are in your blood. These tests may include:
To obtain a sample of your blood, your provider inserts a needle into your vein and removes blood through a tube into a bag or container. This is called phlebotomy.
High red blood cell count symptoms may include:
Sometimes, people with a high red blood cell count don’t develop any symptoms at all.
A high red blood cell count may be a symptom of a disease or disorder. But, it doesn’t always mean that you have a health problem. Health or lifestyle factors can also cause a high red blood cell count.
Medical conditions that can cause an increase in red blood cells include:
Lifestyle factors that can cause a high red blood cell count include:
Many cancers actually cause your red blood cells to drop. However, there are some cancers that can result in a high red blood cell count, including:
It depends on the underlying cause. If a health condition is causing a high red blood cell count, your provider may recommend a procedure or medication to lower it.
If you have polycythemia vera (a rare type of blood cancer), your healthcare provider may prescribe a medicine called hydroxyurea. This will help slow your body’s production of red blood cells. You’ll need to see your provider regularly while taking hydroxyurea to be sure your red blood cell level doesn’t drop too low. Often, people with polycythemia vera also undergo routine blood withdrawals (therapeutic phlebotomy) to keep their red blood cell count under control.
Not necessarily. While a high red blood cell count can indicate a disease or disorder, it doesn’t always mean you have a health condition. Other factors — like living at a high altitude — can also have an impact on your red blood cell count.
But, if you have a high red blood cell count, it’s always a good idea to have additional testing done. This way, your healthcare provider can find the cause and determine if treatment is necessary.
You can’t always prevent a high red blood cell count. But, there are things you can do to lower your risk. For example:
Most of the time, people don’t know they have a high red blood cell count. It’s only discovered when they undergo blood tests for something else.
Talk to your healthcare provider about the results of your blood test. Elevated red blood cells could mean that you have another, underlying health condition.
A note from Cleveland Clinic
Red blood cells play a big role in carrying life-giving oxygen throughout your body. But when your body makes too many, it can cause your blood to thicken and slow, making you more vulnerable to blood clots. Too many red blood cells can also indicate certain health conditions and disorders. If you have a high red blood cell count, it’s important to talk to your healthcare provider. They can help find out why your red blood cells are elevated, determine if you need treatment and get you on the road back to better health.
Last reviewed by a Cleveland Clinic medical professional on 04/25/2022.
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