RBC Count: Tests That Measure Oxygen-Carrying Red Cells in Blood (2024)

The red blood cell (RBC) count is a test that measures the number of oxygen-carrying blood cells in your blood. An abnormal RBC test result is often the first sign of an illness.

A high RBC test result may mean that you have a condition that's preventing you from getting enough oxygen, like chronic obstructive pulmonary disease (COPD). A low RBC test may be caused by an infection, a thyroid condition, or a medical condition related to anemia.

Normal RBC Reference Range

An RBC count is the number of red blood cells per a particular volume of blood. It may be reported in millions of cells per microliter (mcL) of blood or in trillions of cells per liter (L) of blood.

The RBC count reference range varies by sex and age:

• Adult females: 4.2 to 5.4 million/mcL
• Adult males: 4.7 to 6.1 million/mcL
• Children: 4.0 to 5.5 million/mcL

Anything above or below these RBC levels may be concerning. Keep in mind that other factors can influence normal results.

If you live in a high-altitude city like Denver, for example, your blood count will be different than those of people who live in low-altitude areas like the Gulf Coast. For this reason, the ranges cannot be considered hard-and-fast values but just reference points.

High Red Blood Cell Count

A high red blood cell count is called erythrocytosis. It can lead to symptoms of an enlarged spleen, blood clots, and other impacts. Symptoms that can occur with high RBC levels can depend on the cause and include:

• Headache
• Lightheadedness
• Visual changes
• Changes in blood oxygen saturation
• Pruritis (itching)
• Erythromelalgia (a sense of warmth or burning in the hands)

High RBC levels can be due to either a primary cause, or a secondary one linked to medication use or a co-occurring disease that is preventing the body from receiving enough oxygen. Some of these causes include:

• Congenital heart disease
• Heart failure
• Chronic obstructive pulmonary disease(COPD)
• Pulmonary fibrosis
• Misuse of performance-enhancing drugs that stimulate RBC production, such as anabolic steroids or erythropoietin
• Renal cell carcinoma, a type of kidney cancer
• Dehydration

In other cases, factors like high altitude play a role. These factors can include smoking behavior or carbon monoxide poisoning.

Low Red Blood Cell Count

Alow RBC countshows there is a decrease in oxygen-carrying cells in the blood. This is calledanemia. A low RBC count can indicate a serious problem, but not always.

Anemia caused by low red blood cell counts can cause fatigue. Other symptoms include:

• Headaches
• Loss of appetite (anorexia)
• Concentration problems
• Tingling in the hands and feet
• Brittle nails
• Shortness of breath
• Tongue and mouth sores

If left untreated, anemia can lead to life-threatening complications. Various infections, nutritional deficiencies, and medical conditions may cause anemia. Some of these include:

• Kidney failure
• Thyroid problems
• Bleeding, either internal or external
• Leukemia, a type of cancer of white blood cells
• Drug side effects, including chemotherapy
• Multiple myeloma, a type of cancer affecting blood plasma cells
• Deficiency of erythropoietin, a kidney hormone that promotes RBC growth
• Malnutrition (including deficiencies in iron, folate, vitamin B12, or vitamin B6)
• Hemolysis, the abnormal breakdown of red blood cells
• Pregnancy
• Alcohol misuse
• Liver disease
• Burn injuries
• Medications

A low RBC count isn't always serious. For example, your RBC count may be low if you are pregnant or menstruating, or if you aren't getting enough iron in your diet. If you do have a low RBC count, however, you may need tests to rule out more serious causes.

High RBC Count Treatment

Treatment of an abnormal RBC count is typically focused on addressing the underlying condition. These treatments will vary widely depending on the cause, but there are steps you can take to improve your RBC count. If you want to lower RBC count, you can:

• Exercise to improve your heart and lung function.
• Eat less red meat and iron-rich foods.
• Avoid iron supplements.
• Keep yourself well hydrated.
• Avoid diuretics, including coffee and caffeinated drinks, which can dehydrate you.
• Stop smoking, especially if you have COPD or pulmonary fibrosis.
• Avoid the use of steroids, erythropoietin, and other performance-enhancing drugs.

Low RBC Count Treatment

You may be able to increase a low RBC count by:

• Maintaining a healthy, balanced diet, including leafy greens and lean meats
• Taking a daily vitamin to boost iron, folate, vitamin B12, or vitamin B6
• Adding an iron supplement
• Exercising regularly to improve heart and lung function.
• Quitting smoking
• Avoiding aspirin, which reduces clotting and can cause slow blood loss

It's important to treat any underlying conditions that contribute to the anemia. For example, take your thyroid medications as prescribed if you have thyroid problems.

Summary

A red blood cell count is used to measure the number of oxygen-carrying red blood cells in your body. When you have a high blood count or a low blood count, it's a sign that you may be sick.

There are several types of RBC disorders, though, and a range of causes that lead to symptoms. Anemia due to leukemia is treated differently than iron deficiency, and a COPD-related high RBC count is treated differently than one caused by a congenital condition. Your healthcare provider will monitor your RBC count and treat any underlying causes.