I. EVIDENCE FOR THE VALIDITY OF THE ASSAY METHOD AND THE PHYSIOLOGICAL RELEVANCE OF ESTIMATES

Abstract

A radioimmunoassay for erythropoietin (Ep) in human serum is described. Evidence of assay validity included parallelism of dilution curves of the 2nd International Reference Preparation (IRP) (used as standard) with test sera, a fall in serum immunoreactive Ep following blood transfusion and an increase in serum immunoreactive Ep with increasing severity of anemia except in anemias associated with severe renal failure. The geometric mean estimate of serum immunoreactive Ep in 93 normal men and women was 13.3 MIU/ml above the low Ep serum pool used as baseline for the assay. Extrarenal Ep was detectable in the assay and gave a dilution curve parallel to the 2nd IRP.