Erythropoietin

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Also known as: EPO
Formal name: Erythropoietin

At a Glance

Why Get Tested?

To help differentiate between different types of anemia and to determine whether the amount of erythropoietin being produced is appropriate for the level of anemia present

When to Get Tested?

When you have anemia that the doctor suspects may be caused by decreased red blood cell production; when a person is producing too many red blood cells

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

This test measures the amount of erythropoietin in the blood. Erythropoietin is a hormone produced primarily by the kidneys. It is produced and released into the bloodstream in response to low blood oxygen levels (hypoxemia). Erythropoietin is carried to the bone marrow, where it works to stimulate precursor cells to become red blood cells (RBCs). RBCs contain hemoglobin, a protein that carries oxygen throughout the body. Normal RBCs have a lifespan of about 120 days and are usually similar in size and shape.

The body has a dynamic feedback system that attempts to maintain a relatively stable number of RBCs. If too few are produced or too many lost through bleeding or destruction (hemolysis) due to abnormal shape, size, function, or other causes, then the affected person becomes anemic and their ability to transport oxygen diminishes. Normal red blood cell production relies on the functional ability of the bone marrow, on an adequate supply of iron and nutrients such as vitamin B12 and folate, and on an appropriate concentration of and response to erythropoietin.

The amount of erythropoietin released depends upon the severity of the hypoxemia and the ability of the kidneys to produce erythropoietin. The hormone is active for a short period of time and then eliminated from the body in the urine. Increased production and release of erythropoietin continues to occur until oxygen levels in the blood rise to normal or near normal concentrations, then production falls. However, if the kidneys are damaged and/or unable to keep up with the demand for erythropoietin, or if the bone marrow is unable to respond to the stimulation, such as may occur with a bone marrow disorder, then the person typically becomes anemic.

If there is too much erythropoietin produced, as occurs with some benign or malignant kidney tumors and with a variety of other cancers, too many RBCs may be produced (polycythemia). This can lead to an increase in the volume of red cell mass in circulation, an increase in the blood’s viscosity, and sometimes to hypertension, thrombosis, heart attack, or stroke. Rarely, polycythemia is caused by a bone marrow disorder, not by increased erythropoietin. 

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

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(© 1995-2012). Test ID: EPO Erythropoietin (EPO), Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/80173 through http://www.mayomedicallaboratories.com. Accessed April 2012.

Moore, E. and Bellomo, R. (2011 March 21). Erythropoietin (EPO) in acute kidney injury. Annals of Intensive Care 2011, 1:3 [On-line information]. Available online at http://www.annalsofintensivecare.com/content/1/1/3 through http://www.annalsofintensivecare.com. Accessed April 2012.

(Updated 2011 November 14) Kidney Failure: What to Expect. National Kidney and Urologic Diseases Information Clearinghouse [On-line information]. Available online at http://kidney.niddk.nih.gov/kudiseases/pubs/expect/ through http://kidney.niddk.nih.gov. Accessed April 2012.

(Updated 2010 September 9). Anemia in Kidney Disease and Dialysis. National Kidney and Urologic Diseases Information Clearinghouse [On-line information]. Available online at http://kidney.niddk.nih.gov/kudiseases/pubs/anemia/ through http://kidney.niddk.nih.gov. Accessed April 2012.

Lerma, E. and Stein, R. (Updated 2012 March 28). Anemia of Chronic Disease and Renal Failure. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1389854-overview through http://emedicine.medscape.com. Accessed April 2012.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby’s Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 414-415.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Walling, A. (2004 April 1). Erythropoietin Improves Anemia but Not Cancer Control. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20040401/tips/13.html through http://www.aafp.org.

(©2005). Erythropoietin. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.aruplab.com/guides/clt/tests/clt_a241.jsp#1147927 through http://www.aruplab.com.

Hart, J. (2004 January 16). Erythropoietin. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003683.htm.

Eckardt, K. (2001). After 15 years of success—perspectives of erythropoietin therapy. Nephrol Dial Transplant (2001) 16: 1745-1749 [On-line journal]. Available online at http://ndt.oxfordjournals.org/cgi/content/full/16/9/1745 through http://ndt.oxfordjournals.org.

Bahlmann, F. et. al. (2004). Erythropoietin: is it more than correcting anaemia? Nephrol Dial Transplant (2004) 19: 20-22 [On-line journal]. Available online at http://ndt.oxfordjournals.org/cgi/content/full/19/1/20 through http://ndt.oxfordjournals.org.

Denker, B. (2004 March). Erythropoietin: From Bench to Bedside. Nephrology Rounds 2(3) [On-line journal]. Available online at http://www.cardiologyrounds.org/crus/nephUS_0304.pdf#search='erythropoietin' through http://www.cardiologyrounds.org.

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Snively, C. and Gutierrez, C. (2004 November 15). Chronic Kidney Disease: Prevention and Treatment of Common Complications. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20041115/1921.html through http://www.aafp.org.

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U.S. Food and Drug Administration News. FDA Strengthens Safety Information on Erythropoietin-Stimulating Agents (ESAs). (Online information, accessed March 2007). Available online at http://www.fda.gov/bbs/topics/NEWS/2007/NEW01582.html through http://www.fda.gov.

Healthday, MedlinePlus. FDA Tightens Warnings on Anemia Drugs. March 9, 2007. (Online information, accessed April 2007). Available online at http://www.nlm.nih.gov/medlineplus/news/fullstory_46388.html.

Pagana, Kathleen D. & Pagana, Timothy J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 406-407.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition.  Saunders Elsevier, St. Louis, Missouri. Pp 364-365.

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition]. Pp 672.

Grund, S. (2007 August 27, Updated). Erythropoietin test. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003683.htm. Accessed on 11/22/08.

Artunc, F. and Risler, T. (2007 November 6). Serum Erythropoietin Concentrations and Responses to Anaemia in Patients With or Without Chronic Kidney Disease. Medscape from Nephrol Dial Transplant. 2007;22(10): 2900-2908 [On-line information]. Available online at http://www.medscape.com/viewarticle/564922 through http://www.medscape.com. Accessed on 11/22/08.

(2008 October). Anemia in Kidney Disease and Dialysis. National Kidney and Urologic Diseases Information Clearinghouse [On-line information]. Available online at http://kidney.niddk.nih.gov/kudiseases/pubs/anemia/ through http://kidney.niddk.nih.gov. Accessed on 11/22/08.

(2007 August). Your Kidneys and How They Work. National Kidney and Urologic Diseases Information Clearinghouse [On-line information]. Available online at http://kidney.niddk.nih.gov/kudiseases/pubs/yourkidneys/ through http://kidney.niddk.nih.gov. Accessed on 11/22/08.