SERUM IMMUNOREACTIVE ERYTHROPOIETIN IN HEALTH AND DISEASE

Erythropoietin, the glycoprotein which regulates erythropoiesis is uni que amongst the hematopoietic growth factors since it is the only one which behaves like a hormone. Produced primarily in the kidneys in adu lts, erythropoietin interacts with erythroid precursors in the marrow to increase red cell production. Because erythropoietin behaves like a hormone, measurements of erythropoietin in the serum have proved usef ul in determining when production of this hormone is inadequate. Tissu e hypoxia is the only physiologic stimulus for erythropoietin producti on and thus, with anemia, serum erythropoietin levels should be increa sed. Assuming normal marrow function and adequate nutrient supplies, w hen anemia is associated with a low serum erythropoietin level, it can be concluded that the anemia is in part due to erythropoietin lack an d should be correctable by administration of erythropoietin. As a coro llary, a high serum erythropoietin level (greater than 500 mU/ml) in t he presence of anemia suggests that there is end organ failure, and er ythropoietin therapy is not likely to be useful.