High Red Blood Cell Count

What is high red blood cell count?

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.

What is considered a high red blood cell count?

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:

• For people assigned male at birth, 4.7 million to 6.1 million red blood cells per microliter of blood.
• For people assigned female at birth, 4.2 million to 5.4 million red blood cells per microliter of blood.
• For children, 4.0 million to 5.5 million red blood cells per microliter of blood.

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.

What does it mean when your red blood cell count is high?

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.

How can I tell if my red blood cell count is high?

Your healthcare provider can run a number of tests to determine how many red blood cells are in your blood. These tests may include:

• Red blood cell count (RBC).
• Hemoglobin test.
• Hematocrit test.
• Complete blood count (CBC).

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.

Do people with a high red blood cell count develop any symptoms?

High red blood cell count symptoms may include:

• Tiredness.
• Shortness of breath.
• Headaches.
• Blurry vision.
• Sleep disorders.
• Joint pain.
• Itchy skin.
• Numbness and/or tingling.
• Nosebleeds.

Sometimes, people with a high red blood cell count don’t develop any symptoms at all.

What causes a high red blood cell count?

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:

• Heart failure, causing low blood oxygen levels.
• Congenital heart disease (“congenital” means you’re born with it).
• Polycythemia vera (a rare blood cancer in which your bone marrow produces too many red blood cells).
• Kidney tumors.
• Lung disease, such as emphysema, COPD, pulmonary fibrosis (scarring of your lung tissue).
• Hypoxia (low blood oxygen levels).
• Carbon monoxide exposure (usually related to smoking).
• Sleep apnea.

Lifestyle factors that can cause a high red blood cell count include:

• Smoking cigarettes.
• Living at a high altitude.
• Taking performance-enhancing drugs such as anabolic steroids (for example, synthetic testosterone) or erythropoietin.

What cancers cause high red blood cell count?

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:

• Polycythemia vera (a rare blood cancer that causes your body to make too many red blood cells).
• Renal cell carcinoma (the most common type of kidney cancer among adults).
• Hepatocellular carcinoma (the most common type of liver cancer among adults).

Can stress cause a high red blood cell count?

Yes. Research has shown a link between stress and its effect on your blood cells. Stress can lead to an increase in red blood cells, neutrophils (a type of white blood cell) and platelets.

How is a high red blood cell count treated?

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.

Should I worry if my red blood cell count is high?

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.

Can I prevent elevated red blood cells?

You can’t always prevent a high red blood cell count. But, there are things you can do to lower your risk. For example:

• Drink lots of water.
• Avoid coffee, soda and other diuretics.
• Quit smoking.
• Exercise.
• Don’t take iron supplements.
• Don’t take anabolic steroids or other performance-enhancing drugs.
• Use appropriate medical devices, such as a CPAP, if you have sleep apnea.
• If you have heart failure, be sure to follow your healthcare provider’s treatment plan diligently.

When should I see my healthcare provider?

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.