Abstract
Background: Estimation of serum concentrations of free testosterone (FT) and bioavailable testosterone (bioT) by calculation is an inexpensive and uncomplicated method. We compared results obtained with 5 different algorithms. Methods: We used 5 different published algorithms [described by Sodergard et al. (bioTS and FTS), Vermeulen et al. (bioTV and FTV), Emadi-Konjin et al. (bioTE), Morris et al. (bioTM), and Ly et al. (FTL)] to estimate bioT and FT concentrations in samples obtained from 399 independently living men (ages 40-80 years) participating in a cross-sectional, single-center study. Results: Mean bioT was highest for bioTS (10.4 nmol/L) and lowest for bioT E (3.87 nmol/L). Mean FT was highest for FTS (0.41 nmol/L), followed by FTV (0.35 nmol/L), and FTL (0.29 nmol/L). For bioT concentrations, the Pearson correlation coefficient was highest for the association between bioTS and bioTV (r = 0.98) and lowest between bioTM and bioTE (r = 0.66). FTL was significantly associated with both FTS (r = 0.96) and FTV (r = 0.88). The Pearson correlation coefficient for the association between FTL and bioTM almost reached 1.0. Bland-Altman analysis showed large differences between the results of different algorithms. BioTM, bioTE, bioTV, and FT L were all significantly associated with sex hormone binding globulin (SHBG) concentrations. Conclusion: Algorithms to calculate FT and bioT must be revalidated in the local setting, otherwise over- or underestimation of FT and bioT concentrations can occur. Additionally, confounding of the results by SHBG concentrations may be introduced.
| Original language | English |
|---|---|
| Pages (from-to) | 1777-1784 |
| Number of pages | 8 |
| Journal | Clinical Chemistry |
| Volume | 52 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 1 Sep 2006 |
Cite this
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Calculation of bioavailable and free testosterone in men : A comparison of 5 published algorithms. / De Ronde, Willem; Van Der Schouw, Yvonne T.; Pols, Huibert A P; Gooren, Louis J G; Muller, Majon; Grobbee, Diederick E.; De Jong, Frank H.
In: Clinical Chemistry, Vol. 52, No. 9, 01.09.2006, p. 1777-1784.Research output: Contribution to journal › Article › Academic › peer-review
TY - JOUR
T1 - Calculation of bioavailable and free testosterone in men
T2 - A comparison of 5 published algorithms
AU - De Ronde, Willem
AU - Van Der Schouw, Yvonne T.
AU - Pols, Huibert A P
AU - Gooren, Louis J G
AU - Muller, Majon
AU - Grobbee, Diederick E.
AU - De Jong, Frank H.
PY - 2006/9/1
Y1 - 2006/9/1
N2 - Background: Estimation of serum concentrations of free testosterone (FT) and bioavailable testosterone (bioT) by calculation is an inexpensive and uncomplicated method. We compared results obtained with 5 different algorithms. Methods: We used 5 different published algorithms [described by Sodergard et al. (bioTS and FTS), Vermeulen et al. (bioTV and FTV), Emadi-Konjin et al. (bioTE), Morris et al. (bioTM), and Ly et al. (FTL)] to estimate bioT and FT concentrations in samples obtained from 399 independently living men (ages 40-80 years) participating in a cross-sectional, single-center study. Results: Mean bioT was highest for bioTS (10.4 nmol/L) and lowest for bioT E (3.87 nmol/L). Mean FT was highest for FTS (0.41 nmol/L), followed by FTV (0.35 nmol/L), and FTL (0.29 nmol/L). For bioT concentrations, the Pearson correlation coefficient was highest for the association between bioTS and bioTV (r = 0.98) and lowest between bioTM and bioTE (r = 0.66). FTL was significantly associated with both FTS (r = 0.96) and FTV (r = 0.88). The Pearson correlation coefficient for the association between FTL and bioTM almost reached 1.0. Bland-Altman analysis showed large differences between the results of different algorithms. BioTM, bioTE, bioTV, and FT L were all significantly associated with sex hormone binding globulin (SHBG) concentrations. Conclusion: Algorithms to calculate FT and bioT must be revalidated in the local setting, otherwise over- or underestimation of FT and bioT concentrations can occur. Additionally, confounding of the results by SHBG concentrations may be introduced.
AB - Background: Estimation of serum concentrations of free testosterone (FT) and bioavailable testosterone (bioT) by calculation is an inexpensive and uncomplicated method. We compared results obtained with 5 different algorithms. Methods: We used 5 different published algorithms [described by Sodergard et al. (bioTS and FTS), Vermeulen et al. (bioTV and FTV), Emadi-Konjin et al. (bioTE), Morris et al. (bioTM), and Ly et al. (FTL)] to estimate bioT and FT concentrations in samples obtained from 399 independently living men (ages 40-80 years) participating in a cross-sectional, single-center study. Results: Mean bioT was highest for bioTS (10.4 nmol/L) and lowest for bioT E (3.87 nmol/L). Mean FT was highest for FTS (0.41 nmol/L), followed by FTV (0.35 nmol/L), and FTL (0.29 nmol/L). For bioT concentrations, the Pearson correlation coefficient was highest for the association between bioTS and bioTV (r = 0.98) and lowest between bioTM and bioTE (r = 0.66). FTL was significantly associated with both FTS (r = 0.96) and FTV (r = 0.88). The Pearson correlation coefficient for the association between FTL and bioTM almost reached 1.0. Bland-Altman analysis showed large differences between the results of different algorithms. BioTM, bioTE, bioTV, and FT L were all significantly associated with sex hormone binding globulin (SHBG) concentrations. Conclusion: Algorithms to calculate FT and bioT must be revalidated in the local setting, otherwise over- or underestimation of FT and bioT concentrations can occur. Additionally, confounding of the results by SHBG concentrations may be introduced.
UR - http://www.scopus.com/inward/record.url?scp=33748304146&partnerID=8YFLogxK
U2 - 10.1373/clinchem.2005.063354
DO - 10.1373/clinchem.2005.063354
M3 - Article
VL - 52
SP - 1777
EP - 1784
JO - the Journal of Applied Laboratory Medicine
JF - the Journal of Applied Laboratory Medicine
SN - 0009-9147
IS - 9
ER -