An improved enzyme immunoassay for progesterone in human plasma.

Abstract

Abstract We describe an enzyme immunoassay for progesterone in which we use a progesterone-11alpha-hemisuccinyl-horseradish peroxidase conjugate as the "label" and an antiserum raised in rabbits to a progesterone-11alpha-hemisuccinyl-bovine serum albumin conjugate. In this assay, antibody-bound and free steroid are separated by using a second antibody precipitation procedure. The assay has a lower limit of sensitivity of 10 pg/assay tube and satisfies the usual criteria of specificity, precision, and accuracy. Results obtained with a comparison radioimmunoassay and our procedure agreed well (r = 0.98). Eighty samples can be assayed per day. It is not only well suited for surveys where accurate determination of progesterone concentrations in small plasma aliquots is required, but also for monitoring ovulation induction in patients attending infertility clinics.