Evaluation of a direct solid-phase radioimmunoassay for progesterone, useful for monitoring luteal function

We have evaluated a commercially available, direct, solid-phase radioimmunoassay kit for progesterone determination in serum or plasma. The assay is precise, within-run preci-sion (CV) in the clinically significant ranges being 2.5 to 5.2%, between-run 5.5 to 5.8%. Mean analytical recovery of different concentrations of progesterone added to serum was 99.7 % (range 95.3 to 102.7%). Fourteen closelyrelated steroidshowed no cross reactivity. The minimum detection limit was 0.5 g/L. Luteal-phaseprogesteroneconcentra-tions in serum were increased (>3 p.g/L) in 19 normal ovulatory menstrual cycles and decreased (<1.5 g/L) in two nonovulatory cycles. We found this direct assay for proges-terone to be analytically and clinically sound, and useful for assessingluteal-phasefunction. AddItional Keyphrases: steroids “kit”methods document