Development and validation of an in-house radioimmunoassay for erythropoietin

A sensitive radioimmunoassay (RIA) for the determination of erythropoietin (Epo) in blood serum and amniotic fluid has been developed and validated. The assay uses a polyclonal antibody obtained in rabbits immunized with recombinant human Epo by one of the authors. Tracer and second antibody are commercially available. With 100 microliters of sample, the assay can detect 3 U/l. The reproducibility of the assay compares well with commercial Epo RIAs. The normal values estimated in a group of blood donors are slightly higher than those reported for various RIA determinations. The clinical usefulness of the assay was demonstrated by observing the expected increases or decreases of Epo levels in various clinical states known to alter Epo production. The assay meets all requirements of a routine clinical assay at significantly reduced costs, which makes it particularly suitable for use in research applications.