New RIA kit for the determination of progesterone in cows' milk

A new, single-step, specific, simple, economical, and ready to use RIA test for the determination of progesterone in cow's milk was developed. Tubes coated with the specific polyclonal anti-progesterone antibody and progesterone-CMO-125I-histamine as the tracer were used. Progesterone in buffer and fat-free cow's milk, without progesterone were the matrix for the standard curve preparation. Fifty microL of milk and 500 microL of tracer were incubated in the tube for 2 h at room temperature, decanted, and coated. Assay range was 0-270 nmol of progesterone x 1(-1); sensitivity, <1 nmol x 1(-1); recovery, 94-104%; precision as CV%, 2.44-6%.