Calculated free testosterone in hemodialysis and renal transplanted men: Comparison of three equations with each other and with free androgen index

Free testosterone has been shown to correlate better with androgen status than total testosterone. Assessment of free testosterone level has been recommended by all consensus best practice guidelines; however, its direct measurement is laborious and out of the scope of most clinical service laboratories. Calculating its level using some equations has been advocated in the absence of a direct measuring method. Androgen deficiency has been shown to be more prevalent in hemodialysis and renal transplanted patients compared to normal individuals. This study aimed to calculate free testosterone level in those patients using different equations to test whether these equations correlate with each other and with free androgen index. A significant discrepancy was found when these equations were compared with each other and when compared with free androgen index. In conclusion, free testosterone equations gave significantly discordant results when applied to male hemodialysis and renal transplanted patients. Therefore, we recommended validating these equations by free testosterone reference method before applying them to such patients.