Comparison of methods for determination of testosterone and non-protein bound testosterone in men with alcoholic liver disease

Abstract

The serum concentrations of testosterone and of non-protein bound testosterone were determined in 28 men with alcoholic liver disease having normal to decreased serum albumin concentrations and normal to raised SHBG concentrations. Serum testosterone concentrations determined with two radioimmunoassays using different purification procedures and antibody batches did not differ significantly and correlated significantly (r=0.91; p<0.001). The median serum concentration of non-protein bound testosterone was 0.265 nmol/1 (range 0.068-0.495 nmol/l) when determined by equilibrium dialysis and 0.232 nmol/l (range 0.042-0.610 nmol/l) when calculated according to the law of mass action. This difference is insignificant. The concentrations of non-protein bound testosterone determined by the two methods correlated significantly (r=0.83; p<0.001). In the calculation of non-protein bound testosterone, the actual serum albumin concentration can be replaced by a fixed albumin concentration (r=0.99; p<0.001). Further, in these patients the serum concentration of non-protein bound testosterone can be expressed by the testosterone/SHBG ratio (r=0.97; p<0.001).