Site Map

RBC count

Erythrocyte count; Red blood cell count; Anemia - RBC count

An RBC count is a blood test that measures how many red blood cells (RBCs) you have.

RBCs contain hemoglobin, which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work.

Images

Blood test
Formed elements of blood
High blood pressure tests

Animation

Red blood cell production

I Would Like to Learn About:

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

No special preparation is necessary.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

The RBC count is almost always part of a complete blood count (CBC) test.

The test can help diagnose different kinds of anemia (low number of RBCs) and other conditions affecting red blood cells.

Other conditions that may require an RBC count are:

Normal Results

Normal RBC ranges are:

The ranges above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your health care provider about the meaning of your specific test results.

What Abnormal Results Mean

Higher than normal numbers of RBCs may be due to:

Your RBC count will increase for several weeks when you are in a higher altitude.

Drugs that can increase the RBC count include:

Lower-than-normal numbers of RBCs may be due to:

Drugs that can decrease the RBC count include:

Risks

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

Related Information

CBC blood test
Hemoglobin
Peripheral
Splenomegaly
Cor pulmonale
Idiopathic pulmonary fibrosis
Polycythemia vera
Dehydration
Erythropoietin test
Anemia
Hemolytic transfusion reaction
Multiple myeloma
Folic acid in diet
Vitamin B12
Vitamin B6
Alport syndrome
Glucose-6-phosphate dehydrogenase deficiency
Immune hemolytic anemia
Waldenström macroglobulinemia
Paroxysmal nocturnal hemoglobinuria (PNH)
Myelofibrosis
Renal cell carcinoma

References

Bunn HF. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 158.

Chernecky CC, Berger BJ. Red blood cell (RBC) – blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. Philadelphia, PA: Elsevier; 2013:961-962.

BACK TO TOP

Review Date: 2/18/2018  

Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

ADAM Quality Logo

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: verify here.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2019 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.