A sensitive and specific enzymeimmunoassay for serum testosterone

A very sensitive enzymeimmunoassay for testosterone was developed using testosterone-penicillinase conjugate and an antibody to testosterone-3-(O-carboxymethyl)oxime-bovine serum albumin. The specificity of the assay was demonstrated by the fact that estradiol-17 beta, estrone, estriol, progesterone, 17 alpha-hydroxy-progesterone, dehydroepiandrosterone, androstenedione, cortisol and cortisone were ineffective in crossreacting with testosterone while dihydrotestosterone was 8 times less crossreactive as compared to testosterone. The minimum detectable amount of testosterone was 10-15 pg per assay tube. Intra-assay and inter-assay coefficients of variation for samples containing 0.3-6ng/ml of testosterone were 6-8% and 8-10%, respectively. A high degree of correlation (r = 0.97) was observed between serum testosterone values obtained by enzymeimmunoassay and radioimmunoassay. The levels of testosterone in the sera of normal men and women and those in hypogonadal males following stimulation with human chorionic gonadotropin determined by this enzymeimmunoassay appear similar to those reported by other investigators.