A micromethod for the simultaneous determination of clinically important androgens and oestrogens in plasma

A specific micromethod for simultaneous determination of 4-androstenedione, ..5 alpha-dihydrotestosterone, testosterone, oestrone and estradiol-17 beta in 1-2 ml plasma samples is described. Following removal of non-polar hydrophobic compounds in ether extract of plasma using Lipidex 5000 reversed-phase microcolumns, good separation of the steroids for RIA is achieved with straight phase Lipidex 5000 chromatography in microcolumns (4 X 100 mm). The recoveries of the tritiated and non-labelled steroids added to plasma were in the range of 68-96% and 83-105%, respectively. The within-assay and between-assay imprecision (CV) varied from 3.3-9.9% and from 7.7-12.5%, respectively. The detection limit for the different steroids varied from 0.05 nmol/l to 0.17 nmol/l and the assay blanks were negligible. The levels of the five steroids obtained from healthy volunteers agree with those previously reported. It is concluded that the method is reliable and practical for routine analysis of the clinically important androgens and oestrogens in small specimen.