The progesterone EIA is based on the principle of competitive binding between progesterone in the test specimen and progesterone-HRP conjugatefor a constant amount of rabbit antiprogesterone. In the incubation, goat anti-rabbit IgG-coated wells are incubated with 25 μl progesterone standards, controls, patientsamples, 100 μl progesterone-HRP Conjugate Reagent and 50 μl rabbitanti-progesterone reagent at room temperature (18-25