The application of the radioreceptor and radioimmunologic assays in the evaluation of chronic gonadotropin concentrations in blood serum samples of pregnant women

The investigators of gonadotropic hormones are in search of new detection techniques, other than the used radioimmunoassay method (RIA). The latter remains very sensitive, albeit, the specificity of determination is not always proven. The RIA method does not permit to study the biological activity of the hormones. Another technique has been developed recently - the radioreceptor assay (RRA). The gonadotropic activity, determined with the use of this technique is similar to that - determined by biological techniques. It is known that the biological and radioimmunological activities of the gonadotropins vary sometimes to a high range. The presented paper aimed at comparing the applicability of the above-mentioned two techniques (RIA and RRA) for the determination of gonadotropins' concentrations in blood-serum samples collected from pregnant subjects. The hcg concentrations were determined in serum samples collected from 90 pregnant women in different trimester of gestation. The RRA technique gave in majority higher values of hcg activity in comparison with the RIA technique. In all tested samples the RRA demonstrated the presence of hcg, while in 87 samples tested with RIA in 10 the results were false-negative. This implies that the RIA testing may be doubtful, the RRA technique may be treated as a more sure way of pregnancy detection. Another privilege of the latter is a shortening of time of determination to 2-3 hours (comparing with 1-2 days with the aid of RIA). (author)