A method for measurement of free testosterone in premenopausal women involving equilibrium dialysis, chromatography, and radioimmunoassay.
A three-step procedure to evaluate the quantity of true free testosterone in female serum was established. Unbound and bound testosterone were first separated by equilibrium dialysis using undiluted serum. Testosterone in dialysate was extracted and separated from cross-reactive steroids by column chromatography and finally quantified with a sensitive radioimmunoassay. The detection limit of the radioimmunoassay was 2.7 pmol/L and the detection limit of the whole method was 6 pmol/L. The intra-assay coefficients of variation of the method were 20.6%, 16.8%, and 9.5% for free testosterone concentrations 12.0 pmol/L, 21.4 pmol/L, and 31.4 pmol/L, respectively. The interassay coefficients of variation were 26.3% and 14.8% for free testosterone concentrations 10.4 pmol/L and 21.3 pmol/L, respectively. Serum free testosterone concentrations were determined in 27 regularly menstruating control women. The mean concentration of actual free testosterone was 10.0 +/- 4.9 pmol/L (mean +/- SD, range from below 6 to 19 pmol/L, n = 27).
Törmä
A
A
Department of Central Laboratory, Turku University Central Hospital, Finland.
Jaatinen
T A
TA
Kaihola
H L
HL
Koskinen
P
P
Irjala
K
K
D000328:Adult; D015992:Body Mass Index; D002845:Chromatography / Q000379:methods* / Q000706:statistics & numerical data; D003956:Dialysis / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D017697:Premenopause / Q000097:blood*; D011863:Radioimmunoassay / Q000706:statistics & numerical data; D012016:Reference Values; D013739:Testosterone / Q000097:blood*
D013739:Testosterone