 Erythropoietin test
Definition Alternative Names How the test is performed How to prepare for the test How the test will feel Why the test is performed Normal Values What abnormal results mean What the risks are Special considerations DefinitionThe erythropoietin test measures the amount of a hormone called erythropoietin ((EPO) in blood. The hormone acts on stem cells in the bone marrow to increase the production of red blood cells. It is made by cells in the kidney, which release the hormone when oxygen levels are low. See also: Reticulocyte count Alternative NamesSerum erythropoietin; EPO How the test is performedBlood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood. Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding. In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding. 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, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing. Why the test is performedThis test may be used to help determine the cause of anemia, polycythemia (high red blood cells) or other bone marrow disorders. A change in red blood cells will affect the release of EPO. For example, persons with anemia have too few red blood cells, so more EPO is produced. Normal ValuesThe normal range is 0-19 milliunits per milliliter (mU/mL). Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results. What abnormal results meanIncreased EPO levels may be due to secondary polycythemia, an overproduction of red blood cells that occurs in response to an event such as low blood oxygen levels. This may happen at high altitudes or, rarely, because of a tumor that releases EPO. Lower-than-normal EPO levels may be seen in chronic kidney failure, anemia of chronic disease, or polycythemia vera. What the risks areVeins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. Other risks associated with having blood drawn are slight but may include: - Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Special considerationsMathur S, Schexneider K, Hutchison RE. Hematopoiesis. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 30. Physician ReferenceCurrent Procedural Terminology (CPT)82668
Review Date: 8/9/2009
Reviewed By: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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