Serum erythropoietin levels by radioimmunoassay in polycythaemia.
A radioimmunoassay (RIA) method for erythropoietin (Epo) was developed and validated against the polycythaemic mouse assay. The correlation was good, with a r = 0.94. Several other criteria of specificity were also filled by the RIA, which had a lower detection limit of 5 microU/ml. The mean serum-Epo level in 6 patients with secondary polycythaemia, 50.2 +/- 26.2 microU/ml, was significantly higher than in a group of 11 normal subjects, 28.7 +/- 7.2 microU/ml (P less than 0.0002). However, the Epo level in 31 polycythaemia vera (PV) patients, M = 21.9 +/- 6.6 microU/ml, was not significantly different from normal (P = 0.006). Since previous studies with bioassay of heat-treated and concentrated plasma samples have shown a decreased serum-Epo level in PV, Epo levels were measured before and after heat treatment and concentration of samples from normals and polycythaemics. It was found that the levels of immunoreactive material increased after heat treatment and 40 times concentration in samples from normals and patients with secondary polycythaemias, but decreased in PV. We conclude that the Epo levels in serum in the low range measured by our and previous RIA:s probably are not true Epo levels but are partly due to an unspecific serum effect, that was removed by heat treatment.
D000741:Anemia, Aplastic / Q000097:blood / Q000175:diagnosis; D000818:Animals; D000915:Antibody Affinity; D000918:Antibody Specificity; D004921:Erythropoietin / Q000032:analysis*; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D051379:Mice; D011087:Polycythemia Vera / Q000097:blood* / Q000175:diagnosis; D011863:Radioimmunoassay
D007106:Immune Sera; D004921:Erythropoietin