Erythropoietin test: A test of the hormone erythropoietin (EPO) in blood. An abnormal level of EPO may mean bone marrow or kidney disease or EPO abuse.
Testing EPO blood levels is thus of value if:
- Too little EPO might be responsible for too few red blood cells (such as in evaluating anemia).
- Too much EPO might be causing too many red blood cells (polycythemia).
- Too much EPO might be evidence for a kidney tumor.
- Too much EPO in an athlete suggests EPO abuse.
The patient is usually asked to fast for 8-10 hours (overnight) and sometimes to lie quietly and relax for 20 or 30 minutes before the test. The test requires a routine sample of blood.
Normal levels of EPO are 0 to 19 (some say up to 24) mU/ml (milliunits per milliliter). Subnormal values of EPO are found for example in anemia due to chronic kidney failure. Elevated EPO levels are found for example in polycythemia rubra vera, a disorder characterized by an excess of red blood cells. The correct interpretation of an abnormal EPO level depends on the patient's particular picture.