Effectiveness of different diagnostic methods for assessment of hyperandrogenism in young women with hirsutism

Free testosterone is the most common marker of hyperandrogenism in women. Its measurement by equilibrium dialysis and liquid chromatography-tandem mass spectroscopy is the "gold standard", but determination of free testosterone routinely not feasible in all laboratories. In some cases the level of free testosterone may be elevated when the total testosterone level is normal. Low level of sex-hormone binding globulin determines the fraction of plasma testosterone that is free or bound to albumin. Recently, some models for calculating free testosterone and bioavailable testosterone from total testosterone, sex hormone binding globulin and albumin have been developed. The aim of this study was to compare effectiveness of diagnostic methods, such as serum free testosterone measured by ELISA-method and free androgen index and calculated androgen parameters for assessment of hyperandrogenism in young women with hirsutism. In 35 patients with hirsutism and different diagnosis free androgen index, free and bioavailable testosterone were calculated from total testosterone, sex hormone binding globulin and albumin. Free testosterone was measured by Elisa- method. Receiver operating characteristics (ROC) curves were drawn to assess diagnostic power of androgen parametres for different hirsutism degree. Significant positive correlation between free testosterone (FT) measured by ELISA -method and free androgen index (FAI) in patients with hirsutism was detected. The diagnostic power of cFT (calculated free testosterone) was greater than diagnostic power of FT and FAI in the group with severe hirsutism (for severe hirsutism (n=14) auROC (FT) =0,446; auROC (cFT)= 0,507; auROC (FAI)=0,461). FAI, cFT and cBio-T may be more adequate and alternative methods for assessment hyperandrogenism in women with hirsutism, than only free testosterone measured by ELISA-method. Furthermore, the calculated androgen parameters may be important to determinate the mechanisms of hyperandrogenism development.