Predictive accuracy and sources of variability in calculated free testosterone estimates
Gideon Sartorius, Lam P Ly, Ken Sikaris, Robert McLachlan, David J Handelsman
ANNALS OF CLINICAL BIOCHEMISTRY | SAGE PUBLICATIONS INC | Published : 2009
BACKGROUND: Serum free testosterone (FT) concentrations are commonly requested, but because reference FT methods are too laborious various calculational algorithms for FT based on total testosterone (TT) and sex hormone-binding globulin (SHBG) are frequently used. This study provides the first large-scale evaluation of the predictive accuracy and sources of variability for different FT formulae compared with direct laboratory measurements. METHODS: Using a large data-set of direct FT measurements by centrifugal ultrafiltration, the predictive accuracy of five different formulas for cFT (four existing plus a new formula) is evaluated in 3975 consecutive blood samples. In a second data-set of ..View full abstract
Awarded by Swiss National Research Foundation
Gideon Sartorius is Supported by grants of the Swiss National Research Foundation (grant PBBSB-116889) and the Lichtenstein-Stiftung, Basel, Switzerland.