A non-chromatographic radioimmunoassay of progesterone in serum.

Convenient methodology based on separation of progesterone from alcoholic neutral steroids by means of a sulfation-procedure has been developed for the radioimmunoassay (RIA) of progesterone in male and female serum. When coordinated with our previously published non-chromatographic procedure for the RIA of estrone and estradiol in serum, all 3 seteroids can be determined in the same specimen. Validation of the procedure was based on: 1. Agreement between results obtained using ILC and sulfation to fractionate progesterone (r=0.98; b=0.86), 2. accurate recovery of different quantities of progesterone added to serum, 3. independence of the concentration of progesterone and volume of serum used for assay, 4. low procedural blanks (3.6 +/- 1.3 pg), 5. low intraassay (9.7 - 10.3%) and interassay (11.0 - 11.6%) variability and 6. correspondence of observed values for progesterone in male serum (108 +/- 20 pg/ml) and in female serum (follicular, 285 +/- 149 pg/ml; luteal, 3.46 +/- 1.45 ng/ml) with those reported previously by others.