Bioluminescent immunoassays of progesterone: a comparative study of three different procedures

Three bioluminescent immunoassay procedures for the determination of serum progesterone are compared. The sensitivity of the three procedures is similar to the sensitivity of radioimmunoassay (10 pg per tube). The use of a bioluminescent immunosorbent is particularly attractive since it has the simpler protocol. No separation step is required to remove the excess of free label (glucose-6-phosphate dehydrogenase coupled to progesterone). The free enzyme activity is not determined since the bioluminescent reaction occurs in the immunosorbent. The intensity of the signal is greater than with other procedures, and biological components contained in ethyl ether extract do not affect the quality of the assay. A good correlation with a radioimmunoassay using tritiated progesterone is obtained (r2 = 0.96) and coefficients of variation of bioluminescent assays are similar (4 to 12%) to those obtained with commercial radioimmunoassays.