Diagnostic and therapeutic implications of using calculated free testosterone in men with low-normal total testosterone levels
Sudhanshu Chitale1, Krishna Sethia1 & Ketan Dhatariya2
Materials and methods
Twenty-eight men with erectile dysfunction (ED) were investigated with TT, SHBG, albumin, fasting blood glucose, hormonal profile and a lipid profile. Free testosterone and bio-available testosterone (BAT) were calculated in all men using the calculator on the ISSAM website (http://www.issam.ch/freetesto.htm).
Results: The mean age was 55.57 years (range: 276 years±11.48), with a mean body mass index of 29.69 kg/m2 (range: 19.0239.19±4.33). 28.5% had type 2 diabetes. Only 5/28 (17.8%) men had their TT assessed by their primary care physicians prior to referral to the secondary care service. 7/28 (25%) men were clearly hypogonadal based on TT. Of the remaining 21 men with TT in the normal range (927 nmol/l), 13 (61.9%) had TT <14 nmol/l (borderline TT) and 8 (38.1%) had more than 14 nmol/l. 10/13 (76.9%) men with borderline TT had low levels of cFT, and 3/13 had normal levels of cFT. All those with TT>14 nmol/l had normal cFT values. BAT was also lower than normal in 5/10 but within the reference range in 5/10 with low cFT. This is likely to be due to the normal levels of albumin and relatively low levels of SHBG.
Our study highlights the importance of calculating cFT in order to accurately diagnose biochemical hypogonadism in men presenting with clinical hypogonadism but low-normal levels of TT.