DETERMINATION OF SERUM ERYTHROPOIETIN - ITS VALUE IN THE DIFFERENTIAL-DIAGNOSIS OF POLYCYTHEMIAS

In vivo and in vitro bioassays, radio immunoassays (RIA), enzyme linke d immunoassays (ELISA) and immunoradiometric assays (IRMA) have been a pplied to measure serum erythropoietin (Epo) levels. Results are expre ssed in international units (IU). In vivo bioassays are time consuming , expensive and not sensitive enough to measure the amount of Epo in n ormal sera. Nevertheless, this test remains the standard of comparison for the other new assays. Immunologic technics are specific, sensitiv e, reproducible, easy to perform, rapid and are now preferred for the measurement of Epo. Published values for non anemic human range from 6 to 32 IU/l. In the search of etiology of a polycythemia, the results of usual investigations to class the polycythemia either as primitive (P. vera) or secondary are often inconclusive. In these situations, me asurement of serum Epo could be of value for accurate a differential d iagnosis. However the results of the literature and our personal exper ience, show that the serum Epo level does not descriminate with an abs olute fiability between Polycythemia Vera and secondary polycythemia b ecause of a great overlap between the two groups.