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Testosterone Replacement, Low T, HCG, & Beyond
Blood Test Discussion
LabCorp Vs Quest free testosterone lab ranges: Why are they different?
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<blockquote data-quote="madman" data-source="post: 216151" data-attributes="member: 13851"><p>Well aware of Fiers 2018 article.</p><p></p><p>As I have stated previously I am patiently waiting on the completion of Phase II for the TruT (cFTZ) Algorithm let alone standardization and harmonized reference ranges for Free testosterone which is in the works as we speak.</p><p></p><p>Phase II should be coming to an end soon enough.</p><p></p><p>8 years in 2014-2022.</p><p></p><p>Ravi let alone Bhasin are confident about the validity/soon-to-be commercialization of the TruT Algorithm.</p><p></p><p>It's going to happen.</p><p></p><p>He is already pushing the use of the newer calculated method!</p><p></p><p>Bhasin's latest article.</p><p>[URL unfurl="true"]https://www.excelmale.com/forum/threads/testosterone-deficiency-in-men.24722/[/URL]</p><p></p><p></p><p><em><strong>*<u>Free testosterone concentration is ideally measured using the equilibrium dialysis method, performed under standardized conditions</u>.1,31<u> Direct tracer analog methods for measuring free testosterone concentrations are inaccurate, and therefore, their use is not recommended</u>.35 Although several equations to estimate free testosterone concentration from total testosterone, SHBG, and albumin concentrations have been published,36-38 the estimation of free testosterone concentration performed using these equations are predicated upon accurate measurements of total testosterone, SHBG, and albumin concentrations.31,35 <u>Furthermore, equations that are based on a linear model of testosterone’s binding to SHBG assume a fixed binding affinity (approximately 1 nM)31 and ignore the competing presence of other sex steroids, such as dihydrotestosterone and estradiol</u>.</strong></em></p><p><em><strong></strong></em></p><p><em><strong>*Recent studies using modern biophysical techniques have suggested that the <u>binding of testosterone and estradiol to an SHBG dimer is a dynamic process that involves allosteric interactions between binding sites on each of the 2 SHBG monomers such that the binding affinities of the 2 sites are not equivalent</u>.36,39 <strong><u>The binding of a ligand to the first monomer influences the conformational and energetic states of both the monomers</u>.39 <u>The estimation of free testosterone concentration based on an ensemble allosteric model provides a close approximation of concentrations measured using equilibrium dialysis</u>36;</strong></strong></em></p><p><em><strong><strong></strong></strong></em></p><p><em><strong><strong>*<u>the computations of free testosterone concentrations using the ensemble allostery model can be obtained at <a href="https://tru-t.org/" target="_blank">TruT Free Testosterone Calculator by FPT</a></u>. Because of dynamic changes in the binding affinity of SHBG upon ligand binding, depending on the ligand and SHBG concentrations, <u>no equation can accurately estimate free testosterone concentration under all conditions</u>.39</strong></strong></em></p><p></p><p></p><p></p><p></p><p>[ATTACH=full]19283[/ATTACH]</p></blockquote><p></p>
[QUOTE="madman, post: 216151, member: 13851"] Well aware of Fiers 2018 article. As I have stated previously I am patiently waiting on the completion of Phase II for the TruT (cFTZ) Algorithm let alone standardization and harmonized reference ranges for Free testosterone which is in the works as we speak. Phase II should be coming to an end soon enough. 8 years in 2014-2022. Ravi let alone Bhasin are confident about the validity/soon-to-be commercialization of the TruT Algorithm. It's going to happen. He is already pushing the use of the newer calculated method! Bhasin's latest article. [URL unfurl="true"]https://www.excelmale.com/forum/threads/testosterone-deficiency-in-men.24722/[/URL] [I][B]*[U]Free testosterone concentration is ideally measured using the equilibrium dialysis method, performed under standardized conditions[/U].1,31[U] Direct tracer analog methods for measuring free testosterone concentrations are inaccurate, and therefore, their use is not recommended[/U].35 Although several equations to estimate free testosterone concentration from total testosterone, SHBG, and albumin concentrations have been published,36-38 the estimation of free testosterone concentration performed using these equations are predicated upon accurate measurements of total testosterone, SHBG, and albumin concentrations.31,35 [U]Furthermore, equations that are based on a linear model of testosterone’s binding to SHBG assume a fixed binding affinity (approximately 1 nM)31 and ignore the competing presence of other sex steroids, such as dihydrotestosterone and estradiol[/U]. *Recent studies using modern biophysical techniques have suggested that the [U]binding of testosterone and estradiol to an SHBG dimer is a dynamic process that involves allosteric interactions between binding sites on each of the 2 SHBG monomers such that the binding affinities of the 2 sites are not equivalent[/U].36,39 [B][U]The binding of a ligand to the first monomer influences the conformational and energetic states of both the monomers[/U].39 [U]The estimation of free testosterone concentration based on an ensemble allosteric model provides a close approximation of concentrations measured using equilibrium dialysis[/U]36; *[U]the computations of free testosterone concentrations using the ensemble allostery model can be obtained at [URL='https://tru-t.org/']TruT Free Testosterone Calculator by FPT[/URL][/U]. Because of dynamic changes in the binding affinity of SHBG upon ligand binding, depending on the ligand and SHBG concentrations, [U]no equation can accurately estimate free testosterone concentration under all conditions[/U].39[/B][/B][/I] [ATTACH type="full" alt="1643242596562.png"]19283[/ATTACH] [/QUOTE]
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Testosterone Replacement, Low T, HCG, & Beyond
Blood Test Discussion
LabCorp Vs Quest free testosterone lab ranges: Why are they different?
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