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Testosterone Replacement, Low T, HCG, & Beyond
Blood Test Discussion
Reference Intervals for Free Testosterone in Adult Men Measured Using a Standardized Equilibrium Dialysis Procedure
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<blockquote data-quote="madman" data-source="post: 237074" data-attributes="member: 13851"><p>You do realize that the ED device used in Phase 1 (SHBG:T binding) was the same ED device used in Ravi's current study?</p><p></p><p>Remember what I said about waiting on the completion of Phase II?</p><p></p><p></p><p>Aim 3 who knew?</p><p></p><p><em>*In phase I studies, we demonstrated that the TruTTM algorithm provides accurate free T values that match those obtained using the equilibrium dialysis in healthy and hypogonadal men. We have also shown that the binding parameters that have formed the basis of previous equations (e.g., Vermeulen) are incorrect, and that free T values derived using these equations deviate substantially from free T measured by equilibrium dialysis. The phase I studies have led to the adoption of the TruTTM algorithm at several institutions</em></p><p><em></em></p><p><em><strong>*The phase II program</strong> <strong>will continue the development of the TruTTM algorithm by <u>validating it in common conditions characterized by altered SHBG concentrations, such as obesity and aging</u> (AIM 1),</strong> in healthy women across the menstrual cycle, and in women with PCOS (Aim 2). <strong><u>We will generate population-based reference ranges for free T</u> (Aim 3).</strong> Phase II also includes plans for the commercialization of the TruTTM algorithm using a HIPAA-compliant infrastructure for its clinical adoption</em></p><p></p><p></p><p></p><p></p><p>As I already stated in a previous thread.</p><p></p><p>No one should be using/relying upon the newer EAM (TruT™/cFTZ)</p><p>as Phase II is still ongoing and all of the results/data have not come out yet.</p><p></p><p>There has been an ongoing effort behind the scenes to provide further proof of the validity of the TruT™algorithm (cFTZ).</p><p></p><p>Everyone is still waiting!</p><p></p><p>This has to be done.</p><p></p><p>Having a hard time understanding why he is still pushing the newer EAM seeing as they have only completed Phase I and have not provided any further proof of the validity.</p><p></p><p>In one of his more recent lectures (3/2022) and papers (7/2022), he makes it clear where he stands and is still pushing the newer EAM.</p><p></p><p>Definitely has not changed his stance.</p><p></p><p>Seems odd as they would have been sitting on the data I posted here from their most recent paper.</p><p></p><p>Is there something they are sitting on?</p><p></p><p>Your guess is as good as mine!</p><p></p><p>Again we all very well know that when it comes to using any of the calculators for estimating free testosterone cFTV has been the go-to.</p><p></p><p>Already been validated (using assays for TT/SHBG no longer available)/re-validated in 2018 against current state-of-the-art methods.</p><p></p><p>Been in use for over 2 decades now.</p><p></p><p>Fiers camp let alone the CDC and many in the medical community is waiting to see how this unfolds.</p><p></p><p>The CDC is working hard behind the scenes on harmonized/standardization of free testosterone.</p><p></p><p>Still going to be a year or two before this s**t show comes to an end!</p><p></p><p></p><p></p><p></p><p><strong>My reply from a previous thread:</strong></p><p></p><p>This is coming from Fier's camp's most recent paper (posted in the link above).</p><p></p><p>They clearly state <u>for the time being</u>, as they are well aware there is still much going on behind the scenes.</p><p></p><p>Far from over!</p><p></p><p><strong><em>*In contrast we concluded that, although overestimating free T by 20–30%, the formula according to Vermeulen was independent of SHBG, total T, and albumin [221]. Taken into consideration the moderate bias level, but most importantly less influenced by the latter three variables, the <u>Vermeulen formula, for the time being, still appears to be the most robust approximation and deserves our recommendation as a free T calculator for clinical use</u></em></strong></p><p></p><p></p><p></p><p></p><p></p><p></p><p></p><p></p><p>Even then hate to burst your bubble Lil man but highly doubt cFTV let alone cFTZ will come out on top.</p><p></p><p>Remember what I said before or did everyone forget?</p><p></p><p></p><p><strong><em>*Currently, the CDC is developing a <u>harmonized method for free T based on calculated free T using revised formulae</u>. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use</em></strong></p><p></p><p></p><p>Wonder why the f**k they would go and do that!</p><p></p><p></p><p></p><p></p><p></p><p></p><p><strong>Ravi 10/2022</strong></p><p></p><p><em><strong>This study also has some limitations.</strong> These reference ranges were derived from single morning samples, which discount the pulsatile and diurnal secretory rhythms. Previous analyses show that early morning testosterone levels, obtained in a manner similar to that used by physicians in practice, are associated cross-sectionally with symptoms and clinical outcomes (38-40,48). We report reference ranges in men <40 years of age but also provide the distribution of free testosterone levels by age groups. This approach of generating the reference range in healthy young men is analogous to the use of T-scores for bone mineral density.<strong> Although the sample included men of various races and ethnicities, the number of nonwhites was not large enough to offer sufficient power to detect meaningful differences in free testosterone levels among racial or ethnic subgroups.</strong> The data on geographic and racial differences in total testosterone levels are inconsistent (50,51), and no study has examined racial and ethnic differences in free testosterone levels using equilibrium dialysis in different geographic regions of the world. <strong>Additional investigations of multi-ethnic cohorts to evaluate the generalizability of the <u>proposed reference limits</u> to men of other races and ethnicities in different regions of the world are important. <u>Although the sample size was within the IFCC guidelines for analytes with normal distribution, there were relatively small numbers of men within each decade of age and a larger sample size would provide more robust estimates of the reference ranges by age decades</u>.</strong></em></p><p><em><strong></strong></em></p><p><em><strong>Our normative ranges are similar to those reported by pioneers of this field using the legacy method (2) but <u>the percent free testosterone in our reference sample differs from that reported by another laboratory (10,52); this difference in percent free testosterone from that reported by another research laboratory (<2.8%) could be due to differences in buffer composition or in other assay conditions that are not apparent in the published methods (10,52)</u>. </strong>The normative ranges of most commercial laboratories have changed substantially in recent years suggesting changes in their procedures over time (53,54); because procedures used by the commercial laboratories and the details of how reference ranges were derived are not published, an evaluation of these procedures was not feasible.</em></p><p></p><p><strong><em>These reference ranges, generated in a reference sample of healthy men, <u>should not be applied to other assays in other laboratories without appropriate cross-calibration of assays</u>. <u>Differences in study populations, time of sample collection, and testosterone assays can contribute to the differences in reference ranges</u>. <u>The adoption of a standardized procedure for measuring free testosterone and cross-calibration of the testosterone assays against an accuracy-based benchmark such as the CDC's HoST program will facilitate the application of these reference ranges across laboratories</u></em></strong></p><p><strong><em></em></strong></p><p><strong><em>The data here defines reference intervals from a population of healthy nonobese men using a standardized equilibrium dialysis procedure coupled to a HoST-certified LC-MS/MS assay and <u>represent an important first step</u>.</em></strong><em> <strong><u>Further studies are needed to determine how well these reference limits can be applied to the diagnosis of androgen deficiency in clinical populations and in people of different races and ethnicities in different geographic regions</u>. </strong>The association of low free testosterone defined using these criteria with incident outcomes in epidemiologic studies should be studied. Importantly, randomized trials are needed to determine whether testosterone therapy improves outcomes in men, who have free testosterone below these reference limits.</em></p></blockquote><p></p>
[QUOTE="madman, post: 237074, member: 13851"] You do realize that the ED device used in Phase 1 (SHBG:T binding) was the same ED device used in Ravi's current study? Remember what I said about waiting on the completion of Phase II? Aim 3 who knew? [I]*In phase I studies, we demonstrated that the TruTTM algorithm provides accurate free T values that match those obtained using the equilibrium dialysis in healthy and hypogonadal men. We have also shown that the binding parameters that have formed the basis of previous equations (e.g., Vermeulen) are incorrect, and that free T values derived using these equations deviate substantially from free T measured by equilibrium dialysis. The phase I studies have led to the adoption of the TruTTM algorithm at several institutions [B]*The phase II program[/B] [B]will continue the development of the TruTTM algorithm by [U]validating it in common conditions characterized by altered SHBG concentrations, such as obesity and aging[/U] (AIM 1),[/B] in healthy women across the menstrual cycle, and in women with PCOS (Aim 2). [B][U]We will generate population-based reference ranges for free T[/U] (Aim 3).[/B] Phase II also includes plans for the commercialization of the TruTTM algorithm using a HIPAA-compliant infrastructure for its clinical adoption[/I] As I already stated in a previous thread. No one should be using/relying upon the newer EAM (TruT™/cFTZ) as Phase II is still ongoing and all of the results/data have not come out yet. There has been an ongoing effort behind the scenes to provide further proof of the validity of the TruT™algorithm (cFTZ). Everyone is still waiting! This has to be done. Having a hard time understanding why he is still pushing the newer EAM seeing as they have only completed Phase I and have not provided any further proof of the validity. In one of his more recent lectures (3/2022) and papers (7/2022), he makes it clear where he stands and is still pushing the newer EAM. Definitely has not changed his stance. Seems odd as they would have been sitting on the data I posted here from their most recent paper. Is there something they are sitting on? Your guess is as good as mine! Again we all very well know that when it comes to using any of the calculators for estimating free testosterone cFTV has been the go-to. Already been validated (using assays for TT/SHBG no longer available)/re-validated in 2018 against current state-of-the-art methods. Been in use for over 2 decades now. Fiers camp let alone the CDC and many in the medical community is waiting to see how this unfolds. The CDC is working hard behind the scenes on harmonized/standardization of free testosterone. Still going to be a year or two before this s**t show comes to an end! [B]My reply from a previous thread:[/B] This is coming from Fier's camp's most recent paper (posted in the link above). They clearly state [U]for the time being[/U], as they are well aware there is still much going on behind the scenes. Far from over! [B][I]*In contrast we concluded that, although overestimating free T by 20–30%, the formula according to Vermeulen was independent of SHBG, total T, and albumin [221]. Taken into consideration the moderate bias level, but most importantly less influenced by the latter three variables, the [U]Vermeulen formula, for the time being, still appears to be the most robust approximation and deserves our recommendation as a free T calculator for clinical use[/U][/I][/B] Even then hate to burst your bubble Lil man but highly doubt cFTV let alone cFTZ will come out on top. Remember what I said before or did everyone forget? [B][I]*Currently, the CDC is developing a [U]harmonized method for free T based on calculated free T using revised formulae[/U]. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use[/I][/B] Wonder why the f**k they would go and do that! [B]Ravi 10/2022[/B] [I][B]This study also has some limitations.[/B] These reference ranges were derived from single morning samples, which discount the pulsatile and diurnal secretory rhythms. Previous analyses show that early morning testosterone levels, obtained in a manner similar to that used by physicians in practice, are associated cross-sectionally with symptoms and clinical outcomes (38-40,48). We report reference ranges in men <40 years of age but also provide the distribution of free testosterone levels by age groups. This approach of generating the reference range in healthy young men is analogous to the use of T-scores for bone mineral density.[B] Although the sample included men of various races and ethnicities, the number of nonwhites was not large enough to offer sufficient power to detect meaningful differences in free testosterone levels among racial or ethnic subgroups.[/B] The data on geographic and racial differences in total testosterone levels are inconsistent (50,51), and no study has examined racial and ethnic differences in free testosterone levels using equilibrium dialysis in different geographic regions of the world. [B]Additional investigations of multi-ethnic cohorts to evaluate the generalizability of the [U]proposed reference limits[/U] to men of other races and ethnicities in different regions of the world are important. [U]Although the sample size was within the IFCC guidelines for analytes with normal distribution, there were relatively small numbers of men within each decade of age and a larger sample size would provide more robust estimates of the reference ranges by age decades[/U]. Our normative ranges are similar to those reported by pioneers of this field using the legacy method (2) but [U]the percent free testosterone in our reference sample differs from that reported by another laboratory (10,52); this difference in percent free testosterone from that reported by another research laboratory (<2.8%) could be due to differences in buffer composition or in other assay conditions that are not apparent in the published methods (10,52)[/U]. [/B]The normative ranges of most commercial laboratories have changed substantially in recent years suggesting changes in their procedures over time (53,54); because procedures used by the commercial laboratories and the details of how reference ranges were derived are not published, an evaluation of these procedures was not feasible.[/I] [B][I]These reference ranges, generated in a reference sample of healthy men, [U]should not be applied to other assays in other laboratories without appropriate cross-calibration of assays[/U]. [U]Differences in study populations, time of sample collection, and testosterone assays can contribute to the differences in reference ranges[/U]. [U]The adoption of a standardized procedure for measuring free testosterone and cross-calibration of the testosterone assays against an accuracy-based benchmark such as the CDC's HoST program will facilitate the application of these reference ranges across laboratories[/U] The data here defines reference intervals from a population of healthy nonobese men using a standardized equilibrium dialysis procedure coupled to a HoST-certified LC-MS/MS assay and [U]represent an important first step[/U].[/I][/B][I] [B][U]Further studies are needed to determine how well these reference limits can be applied to the diagnosis of androgen deficiency in clinical populations and in people of different races and ethnicities in different geographic regions[/U]. [/B]The association of low free testosterone defined using these criteria with incident outcomes in epidemiologic studies should be studied. Importantly, randomized trials are needed to determine whether testosterone therapy improves outcomes in men, who have free testosterone below these reference limits.[/I] [/QUOTE]
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Testosterone Replacement, Low T, HCG, & Beyond
Blood Test Discussion
Reference Intervals for Free Testosterone in Adult Men Measured Using a Standardized Equilibrium Dialysis Procedure
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