Generally applicable 125iodine-based radioimmunoassays for plasma progesterone

Two methods are described for estimation of plasma progesterone, both employing a heterologous-bridge radioimmunoassay system with antisera raised against a progesterone 11α-hemisuccinate conjugate and a radioiodinated progesterone 11α-glucuronide—tyramine conjugate as tracer. Separation techniques based on double antibody methods have been employed to improve assay precision, and the assays described are sensitive, precise, accurate and robust and well suited to the measurement of progesterone levels for routine monitoring of luteal function. Present evidence suggests that the majority of laboratories which already use such antisera could readily adopt this assay system with its advantages of improved performance and γ-labelled tracer.