Erythrocyte count; Red blood cell count; Anemia - RBC count DefinitionAn RBC count is a blood test that measures how many red blood cells (RBCs) you have. RBCs contain hemoglobin, a protein which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work. How the Test is PerformedA blood sample is needed. How to Prepare for the TestNo special preparation is necessary. How the Test will FeelWhen 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 PerformedThe 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 ResultsNormal 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 MeanHigher than normal numbers of RBCs may be due to:
Your RBC count will increase for several weeks when you are in a higher altitude. Medicines that can increase the RBC count include:
Lower-than-normal numbers of RBCs may be due to:
Medicines that can decrease the RBC count include:
RisksThere 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:
ReferencesGallagher PG. Hemolytic anemias: red blood cell membrane and metabolic defects. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 147. Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Blood disorders. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 124. Means RT Jr. Approach to the anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 144. Pincus MR, Abraham NZ, Bluth M. Interpreting laboratory results. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 9. | |
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Review Date: 3/11/2024 Reviewed By: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. 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. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | |
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