Primus Pathology Laboratory

Red Blood Cell (RBC) Count

Last Updated on July 28, 2022 by Dr. Neeraj Gujar


A red blood cell count determines how many red blood cells you have. It is also known as an erythrocyte count.

An RBC test is important because the hemoglobin in RBCs is essential for oxygen transport to your tissues. The number of RBCs will affect how much oxygen gets to your tissues get. To function properly, your tissues require enough oxygen.

Why Test Is Done?

The Association for Clinical Biochemistry and Laboratory Medicine states that the test is almost always included in a complete blood count (CBC) test. The CBC measures the blood’s components, including

  • Red blood cells
  • White blood cells
  • Platelets
  • Haematocrit
  • Haemoglobin

The volume of red blood cells within your body is called your hematocrit. The hematocrit test is a measure of the blood’s ratio of RBCs.

Platelets are tiny cells that circulate within the bloodstream and form blood clots. These clots allow wounds to heal faster and prevent excess bleeding.

If your doctor suspects that you have a condition affecting RBCs or if you are experiencing low blood oxygen, they may order this test. These may include:

  • Bluish skin color
  • Confusion
  • Restlessness and irritability
  • Problems with breathing

A routine physical examination will often include a CBC. This can provide information about your overall health. It can also be done before surgery.

Your doctor may order the test if you have a medical condition that could affect your RBC count or if you are taking medications that can affect your RBCs. Doctors may use CBCs for monitoring conditions such as leukemia or infections of the blood.

When To Get RBC Test Done?

You could develop symptoms or complications if your RBC count drops too low or too high.

Low RBC counts can lead to symptoms such as

  • Fatigue
  • Breathing difficulty
  • Dizziness or weakness, especially when you make sudden movements
  • Headaches
  • Pale skin
  • Increased heart rate

You could feel the following symptoms if your RBC count is high:

  • Fatigue
  • Breathing difficulty
  • Joint pain
  • Sleep disturbance
  • Tenderness in your hands or soles of feet
  • Itchy skin after a bath or shower

All these symptoms can be a viable reason to get an RBC count.

How To Get Tested?

Man getting his blood drawn for RBC test
Friendly hospital phlebotomist collecting blood sample from patient in lab. Preparation for blood test by female doctor medical uniform on the table in white bright room

RBC count is a part of a complete blood count test. It is done when the doctor prescribes it for diagnosing a health issue. Or you can do it as a part of your annual health checkup routine.

Before the Test

This test does not require any preparation. If you are taking medication, you should inform your doctor. These include all over-the-counter (OTC), drugs and supplements. If any other precautions are necessary, your doctor will let you know beforehand.

During the Test

A simple blood test that includes drawing blood from a vein. A healthcare professional will take blood from your vein, usually at the inside of your elbow. The steps include:

  • Use an antiseptic to clean the puncture site.
  • Wrapping an elastic band around the upper arm increases blood flow to your veins.
  • Gently insert a needle in your vein, and then collect the blood in a tube or vial attached.
  • Removing the elastic band and needle from your arm.
  • The sample will then be sent to a laboratory for analysis.

After The Test

There is always a chance of infection, bleeding, or bruising at the puncture site. The needle may cause moderate pain or a sharp prickling sensation in your arm. You may also feel a bit of dizziness or light-headedness after withdrawing the blood for some time. However, if any of the signs persist, talk to a doctor immediately.

Test Results

RBC ranges can be expressed in microliters (µL). RBC ranges can vary depending on age and gender. However, a normal range guide is:

Normal RBC range (million cells/µL)
Adult (female)4.2 – 5.4
Adult (male)4.7 – 6.1
Child, 1 – 18 years4.0 – 5.5
Infant, 6 – 12 months3.5 – 5.2
Infant, 2 – 6 months3.5 – 5.5
Infant, 2 – 8 weeks4.0 – 6.0
Newborn4.8 – 7.1

These ranges can vary depending on the laboratory. These ranges could also vary for pregnant women.

Interpreting Results

What does a lower-than-average RBC count signify?

Anemia is a condition in which your RBC count is lower than usual. It can result from a decrease or complete loss or destruction of RBCs. Some of the reasons include:

  • Nutritional Deficit

Anaemia caused by iron deficiency is the most common form. However, a lack of nutrients can cause your RBC count to decrease. These are:

  • Copper
  • Vitamin B6
  • Vitamin B9 (folate)
  • Vitamin B12
  • Failure of the Bone Marrow

Rare cases may cause your bone marrow to stop producing new blood cells. This is called aplastic anemia. It could be an autoimmune condition. Aplastic anemia can also be caused by certain drugs, viruses, radiation, and toxins.

  • Haemolysis

Haemolysis refers to the destruction of red blood cell cells. It can be caused by the following:

  • Autoimmune reaction to transfusions of blood
  • Inherited conditions
  • Infection
  • Chronic Conditions

Inflammatory conditions may affect the production of erythropoietin (EPO) in your body. It is a hormone that causes bone marrow cells to produce RBCs. EPO is made in the kidneys. You might have a chronic renal disease that leads to less production of EPO than usual.

Other chronic conditions that can cause low RBC includes but aren’t limited to

  • Autoimmune diseases such as Lupus and rheumatoid arthritis
  • Infections such as tuberculosis and HIV
  • Cancers such as multiple myeloma and leukemia
  • IBD such as ulcerative colitis and Crohn’s disease
  • Other conditions

There are other possible causes for a lower RBC count than usual:

  • Medications

You may also experience a drop in your RBC count if you take certain drugs, such as:

  • Chemotherapy drugs
  • Quinidine used to treat irregular heartbeats
  • Chloramphenicol used to treat bacterial infections
  • Hydantoins are used as a traditional treatment for epilepsy and muscle spasms.

What does an RBC count higher than normal mean?

Erythrocytosis is a condition where your RBC count exceeds the normal. This can cause your blood to thicken than normal, and increase your risk for blood clots.

  • Primary Erythrocytosis

Primary erythrocytosis occurs when your body produces more RBCs. This happens when your bone marrow cells are damaged. This condition can often be passed down from one generation to another.

One example of such a condition is Polycythaemia Vera. This is a bone marrow disorder that causes an overproduction of RBCs. It is also associated with a genetic mutation.

  • Secondary Erythrocytosis

Secondary erythrocytosis occurs when an external factor raises your RBC count. This could be caused by a drug, disease, or other cause.

  • Other Medical Conditions

A high level of red blood cells can be caused by some medical conditions, such as:

  • Congenital cardiac disorder
  • Respiratory disorders include pulmonary fibrosis, COPD, or even sleep apnoea
  • Cysts, kidney disease, and other renal disorders
  • Certain tumors such as hepatocellular cancer and renal cell carcinoma
  • Medications

Some drugs may increase your RBC count.

  • Gentamicin is an antibiotic that’s used to treat blood bacterial infections.
  • Performance-enhancing drugs such as protein injections or anabolic steroids
  • Methyldopa is often used to treat high blood pressure
  • Diuretics
  • Lifestyle Reasons

There are other possible lifestyle reasons why your RBC count is elevated such as:

  • Smoking
  • Living at a higher elevation
  • Blood doping
  • Dehydration

What To Do in Case of Abnormal Levels?

Any abnormal results should be discussed with your doctor. They may order additional tests depending on the results.

These include blood screening where a sample of your blood is taken and examined under a microscope. A blood smear can detect abnormalities in blood cells, such as sickle cell disease and white blood cell disorders like leukemia. It also helps to identify bloodborne parasites such as malaria.

A bone marrow biopsy will show you how different cells in your blood are formed within your bone. Diagnoses such as ultrasound and electrocardiogram can be used to determine if any conditions affect the heart or kidneys.

Low RBC Count Treatment

All forms of anemia need treatment. The cause of your anemia will determine the treatment you need.

  • Iron deficiency: Take iron supplements. Infusions can be given through your veins.
  • Vitamin deficiency: Take vitamin supplements.
  • Bone marrow loss: Your doctor might prescribe medications. You may need a bone transplant if medications fail to help.
  • Chronic conditions: The doctor will typically focus on the underlying cause. Sometimes they might prescribe an EPO-stimulating drug.
  • Blood loss: Transfusions can increase the RBCs in your body.

High RBC Count Treatment

Regular phlebotomy may be necessary if you have erythrocytosis. This is a procedure that removes some blood from the body to lower your RBC.

Your doctor may recommend hydroxyurea to lower your RBC count if phlebotomies fail. Aspirin may also come in handy to prevent blood clots.

Lifestyle Changes

Women tying laces of her running shoes

Lifestyle changes can affect your RBC count.

Some lifestyle changes that can increase your RBC count:

  • Maintaining a healthy diet, and avoiding vitamin deficiencies
  • Reducing alcohol consumption
  • Regular exercise
  • Avoiding aspirin

Some lifestyle changes that can help you decrease your RBC count:

  • Reduce the amount of red meat and iron you eat
  • Avoid diuretics such as drinks containing caffeine and alcohol
  • Drink more water
  • Quit smoking

Dietary Changes

Home treatment can be made easier by adjusting your diet and managing your RBC count.

With the following dietary modifications, you may be able to raise your RBC:

  • You can add iron-rich food to your diet (such as meats, fish, poultry, and tofu) as well as dried beans, peas, and leafy green vegetables.
  • Increasing copper intake through foods such as shellfish, poultry, or nuts.
  • Vitamin B12 foods like eggs, meats, and fortified cereals are good options.

Final Takeaway

A high or low RBC count can lead to serious health problems. You can manage your RBC count by yourself, starting with regular exercise and a healthy diet. These lifestyle and dietary changes are especially important if you have any chronic diseases or blood cancers that could affect your RBC count.

If you feel tired or have trouble breathing, consult a doctor. These symptoms are usually signs of an abnormal RBC count. To get an RBC test simply visit a diagnostic center or contact one that can take the RBC test at home.


When To Get Tested?

If your doctor suspects that you have health problems causing symptoms or complications related to your RBC count such as your RBC count dropping too low or too high.

How to increase RBC count?

Eating an iron-rich diet can increase your body’s production of RBCs. Along with that make sure that you include nutrients such as folic acid, vitamin B-12, copper, and vitamin A in your diet.

Why RBC count is low?

Low RBC counts could also be a sign of a vitamin D6, B12, or folate deficiency. This could also indicate internal bleeding, kidney disease, or malnutrition (where the body doesn’t receive enough nutrients).

What happens if the RBC count is low?

Anemia (also known as low RBC count) can cause a decrease in the body’s ability to transport nutrients and oxygen around the cardiovascular system. It can lead to fatigue, dizziness, and heart palpitations. Iron deficiency anemia is the most common type and could be due to blood loss, malnutrition, or kidney problems.

Does exercise increase red blood cells?

Exercise can increase total hemoglobin or red cell mass which increases oxygen-carrying ability. Yet to increase the count you need to indulge in an iron-rich diet.

by Dr. Neeraj Gujar

Dr. Neeraj Gujar has done his M.D. in Pathology from Government Medical College. He has worked at various organisations such as Breach Candy Hospital and Tata Memorial Hospital along with many other private organisations. During his working career, he realised the pressing need for exceptional quality diagnostic services. A diagnostic centre that can consistently give accurate results verified by a consultant doctor (M.D. Pathologist) on which your doctor can depend. This has been the founding principle of Primus Pathology and Diagnostics.

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