[Radioimmunologic determination of growth factors. II. Comparative development of methods for the determination of hematopoietic growth factors].

On the basis of our long-term experience, presented are the current clinically useful methods for determining erythropoietin, the granulocytopoiesis growth factor and thrombocytopoietin with the results in their use. Facts are shown, concerning the long-used method of determining erythropoietin through the use of the biological test on polycythemic mice. In our conditions, mice treated with physiological solution (negative controls) have a Fe-59 incorporation below 0.5% of the given dose, while 0.2 units of the international erythropoietin standard (positive control) increases that incorporation to 3.0%. Also presented, are results of determining erythropoietin by means of the newest immunometric method which has shown exceptional features: the whole procedure, including necessary rinsings, lasts about six hours, and it is possible, in the course of one work day, to all at once precisely determine the erythropoietin concentration in 80 samples of human serum. This fact, as well as the outstanding sensitivity of the method which is about 2 mJ/ml (that is 50 times the sensitivity of the biological test) has as a result, the wide introduction of erythropoietin determination in the clinical use of today and the definition of its clinical importance. The measurement range of the method is from 2-200 J/L which can be extended further by specimen dilution. It is especially important that duplicate measurements at one point of the curve almost coincide, which indicates great method precision. The lowest measured concentration in our series amounted to 0 J/L and the greatest to greater than 250 J/L. Elevated values were found in 17 of the 114 serums.(ABSTRACT TRUNCATED AT 250 WORDS)