Quest Lab values from DiscountedLabs.com just not adding up

[drpub2112]

So I'm pretty new to this TRT thing and I'm still getting my arms around some of the discussion here. From what I've gathered:

1) LC/MS is the most accurate method for testing Total Testosterone
2) Equilibrium Dialysis method is the gold standard for testing Free Testosterone.

I've done a fair amount of testing, apparently using less reliable methods, so I ordered the Quest Total and Free Testosterone from discountlabs.com using the methods listed above. In comparison to my TT from LabCorp using RIA method, I dropped from 1008 ng/dL to 756 ng/dL. I'm assuming that the Quest value of 756 would be the more accurate because it was done using LC/MS.

The FT (EQ Dialysis) came in at 169 pg/ml with a range of 35-155.

Here is the gist of my confusion.

My understanding is that the TT and FT are ordered together as a set because the Dialysis FT test arrives at a percentage and then applies that value to the TT value (and is then multiplied by 10 to get pg/ml).

The reference range for the TT (LC/MS) is 250 - 1100 ng/dL.
The reference range for the FT (Dialysis) is 3.5 - 15.5 ng/dL. (35-155 pg/ml)

That means that if someone has a TT of 1100, then the top of their FT range is 1.4%. This seems completely implausible. 1.4% free is lousy.

My result are :

TT - 756 ng/dL (250 - 1100 ng/dL)
FT - 16.9 ng/dL (2.2%) (3.5 - 15.5 ng/dL)

So according to them, I'm near the middle of the range for TT and well above the top of their range for FT @2.23% unbound?

The FT and the percentage are completely plausible, especially since online FT calculators all put me at ~2.2% free. The issue is with the lab's range. If EQ Dialysis is the gold standard for measuring FT, and healthy men have at or above 2% free T, then the stated range on the lab test is completely impossible and unreliable. The only thing it can do is make people think their FT is super high when it's not.

Am I missing something here???

I just want to understand if EQ dialysis and Vermeulen Calc both put me @ ~17 ng/dL (2.2%) free, am I really just mediocre FT compared to optimized (20-30 ng/dL), or am I supraphysiological 17 ng/dL, according to Quest's proprietary sampling? Should I believe the percentage or the range?

It's particularly confusing because my LabCorp Total T (RIA) test of 1008 ng/dL calculates to 23.5 ng/dL = 2.33 %. If that's the case, then I'm probably more dialed in than I think I am.

Thanks for any help. I know you guys see a lot of repeated questions here. Would love it if this stuff was standardized. Imagine if cholesterol and blood sugar labs were this screwed up!

 

[Vince]

This thread by Nelson may help.

What is a Normal Blood Level of Testosterone? What Do Guidelines Say?

Normal values may vary from lab to lab depending on what reference range they use. Depending on the country, ranges are in nanograms per deciliter (usually in the United States) or nanomoles per liter (Europe and other countries). The conversion factor is: Click here: What’s a “Normal”...

www.excelmale.com

 

[FunkOdyssey]

Am I missing something here???

Yes. What you're missing is that in natural men, the highest total testosterone values are not posted by men with a high percentage of free T. The highest total testosterone values belong to the high SHBG guys. High SHBG drives your total testosterone way up relative to your free T, and consequently your free testosterone as a percentage is lower. With this in mind, it is very plausible that the average guy with 1100 ng/dL total testosterone has 1.4% free.

Also, I would note that Quest's free testosterone by equilibrium dialysis usually produces lower results than Vermeulen calculations by 20-30%. The range you quoted for optimized men, which represents more of a TOT idea of what optimized means, refers to Vermeulen calculated values. You'll want to use your own Vermeulen values then to compare apples to apples.

 

[drpub2112]

Yes. What you're missing is that in natural men, the highest total testosterone values are not posted by men with a high percentage of free T. The highest total testosterone values belong to the high SHBG guys. High SHBG drives your total testosterone way up relative to your free T, and consequently your free testosterone as a percentage is lower. With this in mind, it is very plausible that the average guy with 1100 ng/dL total testosterone has 1.4% free.

With that said, Quest's free testosterone by equilibrium dialysis usually produces lower results than Vermeulen calculations by 20-30%. The range you quoted for optimized men, which represents more of a TOT idea of what optimized means, refers to Vermeulen calculated values. You'll want to use your own Vermeulen values then to compare apples to apples.

Thanks man, that is very helpful!

My SHGB is always 28-30mnol, even before TRT. I'm doing daily 16mg subq Cyp injections so I guess that isn't really driving my SHGB up or down. I don't use any ancillaries.

My Vermeulen Calc is 16.7 ng/dL = 2.2 % if I use the LC/MS TT from Quest (756ng). It's 23.5 ng/dL = 2.33 % if I use the RIA TT I get from LabCorp (1008ng). Either way, the percentage is the same, it's just the absolute value that's different.

Assuming the 756 ng/dL is the more accurate TT result, with SHGB @30 and albumin 4.9, I calculate to 16.7 ng/dL free. I don't want to chase numbers or end up supraphysiological. I just don't want to underdose and never feel optimized. I still feel terrible after about 7 weeks at this level.

I know that 750 is a respectable TT so I'll probably hold for a little while longer before making any conclusions. My Sensitive E2 is ~35 pg/dL from both labs and is also basically unchanged from before TRT just like my SHGB.

With that said, Quest's free testosterone by equilibrium dialysis usually produces lower results than Vermeulen calculations by 20-30%.

Thanks for the insight! In my case, both the calc and the Dialysis get the same result and percentage, using the same Total T.

 

[FunkOdyssey]

Here's an example from today on t-nation of a natural high test man with total and free T results from Quest. You'll note he is generally not exceeding their range for free test and has high SHBG:

Naturally High Test & Estradiol, Still Feel Awful

Hello. I’m 37 years old and have naturally high testosterone (usually over 1000 ng/dl) but still feel like shit in general. For the past 6 months or so I have been experiencing some strange symptoms (nipples have a dull surging ache at various times) so I went ahead and started monitoring my...

forums.t-nation.com

 

[madman]

So I'm pretty new to this TRT thing and I'm still getting my arms around some of the discussion here. From what I've gathered:

1) LC/MS is the most accurate method for testing Total Testosterone
2) Equilibrium Dialysis method is the gold standard for testing Free Testosterone.

I've done a fair amount of testing, apparently using less reliable methods, so I ordered the Quest Total and Free Testosterone from discountlabs.com using the methods listed above. In comparison to my TT from LabCorp using RIA method, I dropped from 1008 ng/dL to 756 ng/dL. I'm assuming that the Quest value of 756 would be the more accurate because it was done using LC/MS.

The FT (EQ Dialysis) came in at 169 pg/ml with a range of 35-155.

Here is the gist of my confusion.

My understanding is that the TT and FT are ordered together as a set because the Dialysis FT test arrives at a percentage and then applies that value to the TT value (and is then multiplied by 10 to get pg/ml).

The reference range for the TT (LC/MS) is 250 - 1100 ng/dL.
The reference range for the FT (Dialysis) is 3.5 - 15.5 ng/dL. (35-155 pg/ml)

That means that if someone has a TT of 1100, then the top of their FT range is 1.4%. This seems completely implausible. 1.4% free is lousy.

My result are :

TT - 756 ng/dL (250 - 1100 ng/dL)
FT - 16.9 ng/dL (2.2%) (3.5 - 15.5 ng/dL)

So according to them, I'm near the middle of the range for TT and well above the top of their range for FT @2.23% unbound?

The FT and the percentage are completely plausible, especially since online FT calculators all put me at ~2.2% free. The issue is with the lab's range. If EQ Dialysis is the gold standard for measuring FT, and healthy men have at or above 2% free T, then the stated range on the lab test is completely impossible and unreliable. The only thing it can do is make people think their FT is super high when it's not.

Am I missing something here???

I just want to understand if EQ dialysis and Vermeulen Calc both put me @ ~17 ng/dL (2.2%) free, am I really just mediocre FT compared to optimized (20-30 ng/dL), or am I supraphysiological 17 ng/dL, according to Quest's proprietary sampling? Should I believe the percentage or the range?

It's particularly confusing because my LabCorp Total T (RIA) test of 1008 ng/dL calculates to 23.5 ng/dL = 2.33 %. If that's the case, then I'm probably more dialed in than I think I am.

Thanks for any help. I know you guys see a lot of repeated questions here. Would love it if this stuff was standardized. Imagine if cholesterol and blood sugar labs were this screwed up!

With a robust TT 756 ng/dL and normal SHBG 30 nmol/L, you can rest assured that your FT level is healthy.

Put money on it if you had your FT tested using Labcorp's TT (LC/MS-MS) with FT (Equilibrium Ultrafiltration) your FT would be near the top-end of the assay reference range 5.00-21.00ng/dL.

070038: Testosterone, Free, Equilibrium Ultrafiltration With Total Testosterone, LC/MS-MS | Labcorp

Labcorp test details for Testosterone, Free, Equilibrium Ultrafiltration With Total Testosterone, LC/MS-MS

www.labcorp.com

post #35

Could this be low E2?

I don't know what to make of these results. I've got crazy high total and E2, with average free. I think I can rule out my protocol having anything to do with my joint pain, so that's a positive. And like I had said, sexually I've been good, which was my whole reason for trt in the first place...

www.excelmale.com

My reply:

For the time being stick to testing your FT using Equilibrium Dialysis or Ultrafiltration, especially in cases of ALTERED SHBG!

Test using the same lab/same assay (most accurate).

Compare your blood work using the same lab/same assay (most accurate).

Forget using/relying upon the calculated methods in cases of altered SHBG until this S**TSHOW comes to an end which will be soon enough.

If you want to use/rely on the calculated methods then go F**KING NUTS!

*Currently, the CDC is developing a harmonized method for free T based on calculated free T using REVISED FORMULAE. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use

Now, why the F**K would they go and do that?



Key Points:

* Limitations of using free testosterone by equilibrium dialysis and calculated free testosterone concentrations in practice are the lack of assay standardization, an accuracy-based quality control program, and a harmonized reference range. Until these limitations are addressed, free testosterone by equilibrium dialysis and calculated free testosterone should use reference ranges established by individual laboratories or their specific assay method

*Assays that are standardized are designed to provide accurate results, traceable to “true” value-assigned certified reference materials and gold-standard reference methods. Results obtained using standardized methods can be compared across assays, institutions, populations, and past and future test results, thereby improving diagnosis, treatment, and outcomes of patients




The Need to Harmonize Clinical Laboratory Test Results-----

Laboratory test results are a critical component of patient care. These values help physicians diagnose disease and are critical to developing clinical guidelines that direct treatment options and are instrumental in ongoing efforts to improve and measure the quality of patient care. Most tests report a numeric value for healthcare providers to interpret and the range of numbers reported for a test for a certain condition may vary depending on the method used

Different test methods, however, may report different numeric values for the same condition. Although these test results may be accurate within the context of its own method, this variation can create confusion for physicians and patients. Clinical laboratory test results need to be harmonized so that healthcare providers and the public receive the same numeric result regardless of the method or instrument used or the setting where it was performed

CDC STANDARDIZED TOTAL T and ESTRADIOL ASSAYS and soon to be FREE TESTOSTERONE!

How the CDC Clinical Standardization Programs Are Improving Hormone Tests - AACC.org WHAT PROGRESS HAS CDC MADE WITH STANDARDIZING TOTAL TESTOSTERONE AND ESTRADIOL TESTS? Since HoSt began in 2010, CDC has had more than 350 participants in 15 countries. Participants have shown measurable...

www.excelmale.com

*Measuring FT is technically challenging and shows high variability. The CDC clinical standardization program is developing a high throughput method using the gold-standard equilibrium dialysis (ED) procedure with isotope dilution ultra-high-performance liquid chromatography-tandem mass spectrometry (ID-UHPLC-MS/MS)

This has been done now!

@Nelson Vergel

You heard it here first only on Excel (dropping the thread soon)!

CDC has developed a new higher-order reference method with high throughput FT ED UHPLC-MS/MS.

The method was used to evaluate the agreement between measured and calculated (cFTV).

N=45

The data in one of the slides show that a majority of the calculated values overestimated FT concentration compared to measured values (new higher-order reference method with high throughput ED UHPLC-MS/MS).

The mean bias is roughly 35% and a higher bias (upwards of 60%) was seen in the samples with low FT concentrations.


*The CDC ED-UPLC/MS/MS FT high-throughput method shows sufficient accuracy, precision, and sensitivity and is suitable for routine FT measurements in patient care and research settings

*The CDC ED-UPLC/MS/MS FT method can provide more accurate FT estimations compared to cFT by Vermeulen formula

CDC Hormone Standardization Program (CDC HoSt) Certified Free Testosterone Procedures is coming!

www.excelmale.com

What to Measure: Testosterone or Free Testosterone?

What to Measure: Testosterone or Free Testosterone? (2021) Christina Wang and Ronald Swerdloff 1.1 Why Serum Testosterone Is Necessary for the Diagnosis of Testosterone Deficiency? Low serum testosterone (T) levels in adult men can lead to significant clinical symptoms and signs of...

www.excelmale.com

*The binding of T to SHBG is complex, which results in many different methods that directly measure or calculate free T. Some of these methods do not measure the free fraction of T and some formulae may provide less accurate results [40]

*Recent evidence suggests that the law of mass action formula which is based on the assumption that two T molecules bind to two binding sites on the SHBG with similar binding affinity may be incorrect. And further argues that the binding of T to SHBG may be a multistep, dynamic process with complex allosteric characteristics [65]. Based on this new model, investigators used a new formula to calculate free T in younger men in the Framingham Heart Study and showed that the newly calculated values were similar to those measured by equilibrium dialysis. They further verified that the calculated free T values had clinical diagnostic validity using data from the European Male Aging Study

*Currently, the CDC is developing a harmonized method for free T based on calculated free T using revised formulae. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use

*Perhaps the newer formula for calculated free T validated in multiple laboratories [65], will become generally available, correlate with free T by equilibrium dialysis, and demonstrate improved correlation with clinical symptoms and therapeutic responsiveness. If all these prove to be true, then this formula to calculate free T may be a justified replacement for free T measurement by the equilibrium dialysis methodology

What's Coming? Accurate measurement of total and free testosterone levels for the diagnosis of androgen disorders

Accurate measurement of total and free testosterone levels for the diagnosis of androgen disorders (7/2022) Ezgi Caliskan Guzelce, MD, Clinical/ Research Fellow, Francesca Galbiati, MD, Fellow, Anna L. Goldman, MD, Assistant Professor of Medicine, Arijeet K. Gattu, MD, Fellow, Shehzad Basaria...

www.excelmale.com

 

[tareload]

With a robust TT 756 ng/dL and normal SHBG 30 nmol/L, you can rest assured that your FT level is healthy.

Put money on it if you had your FT tested using Labcorp's TT (LC/MS-MS) with FT (Equilibrium Ultrafiltration) your FT would be near the top-end of the assay reference range 5.00-21.00ng/dL.

070038: Testosterone, Free, Equilibrium Ultrafiltration With Total Testosterone, LC/MS-MS | Labcorp

Labcorp test details for Testosterone, Free, Equilibrium Ultrafiltration With Total Testosterone, LC/MS-MS

www.labcorp.com

post #35

Could this be low E2?

I don't know what to make of these results. I've got crazy high total and E2, with average free. I think I can rule out my protocol having anything to do with my joint pain, so that's a positive. And like I had said, sexually I've been good, which was my whole reason for trt in the first place...

www.excelmale.com

My reply:

For the time being stick to testing your FT using Equilibrium Dialysis or Ultrafiltration, especially in cases of ALTERED SHBG!

Test using the same lab/same assay (most accurate).

Compare your blood work using the same lab/same assay (most accurate).

Forget using/relying upon the calculated methods in cases of altered SHBG until this S**TSHOW comes to an end which will be soon enough.

If you want to use/rely on the calculated methods then go F**KING NUTS!

*Currently, the CDC is developing a harmonized method for free T based on calculated free T using REVISED FORMULAE. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use

Now, why the F**K would they go and do that?



Key Points:

* Limitations of using free testosterone by equilibrium dialysis and calculated free testosterone concentrations in practice are the lack of assay standardization, an accuracy-based quality control program, and a harmonized reference range. Until these limitations are addressed, free testosterone by equilibrium dialysis and calculated free testosterone should use reference ranges established by individual laboratories or their specific assay method

*Assays that are standardized are designed to provide accurate results, traceable to “true” value-assigned certified reference materials and gold-standard reference methods. Results obtained using standardized methods can be compared across assays, institutions, populations, and past and future test results, thereby improving diagnosis, treatment, and outcomes of patients




The Need to Harmonize Clinical Laboratory Test Results-----

Laboratory test results are a critical component of patient care. These values help physicians diagnose disease and are critical to developing clinical guidelines that direct treatment options and are instrumental in ongoing efforts to improve and measure the quality of patient care. Most tests report a numeric value for healthcare providers to interpret and the range of numbers reported for a test for a certain condition may vary depending on the method used

Different test methods, however, may report different numeric values for the same condition. Although these test results may be accurate within the context of its own method, this variation can create confusion for physicians and patients. Clinical laboratory test results need to be harmonized so that healthcare providers and the public receive the same numeric result regardless of the method or instrument used or the setting where it was performed

CDC STANDARDIZED TOTAL T and ESTRADIOL ASSAYS and soon to be FREE TESTOSTERONE!

How the CDC Clinical Standardization Programs Are Improving Hormone Tests - AACC.org WHAT PROGRESS HAS CDC MADE WITH STANDARDIZING TOTAL TESTOSTERONE AND ESTRADIOL TESTS? Since HoSt began in 2010, CDC has had more than 350 participants in 15 countries. Participants have shown measurable...

www.excelmale.com

*Measuring FT is technically challenging and shows high variability. The CDC clinical standardization program is developing a high throughput method using the gold-standard equilibrium dialysis (ED) procedure with isotope dilution ultra-high-performance liquid chromatography-tandem mass spectrometry (ID-UHPLC-MS/MS)

This has been done now!

@Nelson Vergel

You heard it here first only on Excel (dropping the thread soon)!

CDC has developed a new higher-order reference method with high throughput FT ED UHPLC-MS/MS.

The method was used to evaluate the agreement between measured and calculated (cFTV).

N=45

The data in one of the slides show that a majority of the calculated values overestimated FT concentration compared to measured values (new higher-order reference method with high throughput ED UHPLC-MS/MS).

The mean bias is roughly 35% and a higher bias (upwards of 60%) was seen in the samples with low FT concentrations.


*The CDC ED-UPLC/MS/MS FT high-throughput method shows sufficient accuracy, precision, and sensitivity and is suitable for routine FT measurements in patient care and research settings

*The CDC ED-UPLC/MS/MS FT method can provide more accurate FT estimations compared to cFT by Vermeulen formula

CDC Hormone Standardization Program (CDC HoSt) Certified Free Testosterone Procedures is coming!

www.excelmale.com

View attachment 25106
View attachment 25105
View attachment 25107
View attachment 25108

What to Measure: Testosterone or Free Testosterone?

What to Measure: Testosterone or Free Testosterone? (2021) Christina Wang and Ronald Swerdloff 1.1 Why Serum Testosterone Is Necessary for the Diagnosis of Testosterone Deficiency? Low serum testosterone (T) levels in adult men can lead to significant clinical symptoms and signs of...

www.excelmale.com

*The binding of T to SHBG is complex, which results in many different methods that directly measure or calculate free T. Some of these methods do not measure the free fraction of T and some formulae may provide less accurate results [40]

*Recent evidence suggests that the law of mass action formula which is based on the assumption that two T molecules bind to two binding sites on the SHBG with similar binding affinity may be incorrect. And further argues that the binding of T to SHBG may be a multistep, dynamic process with complex allosteric characteristics [65]. Based on this new model, investigators used a new formula to calculate free T in younger men in the Framingham Heart Study and showed that the newly calculated values were similar to those measured by equilibrium dialysis. They further verified that the calculated free T values had clinical diagnostic validity using data from the European Male Aging Study

*Currently, the CDC is developing a harmonized method for free T based on calculated free T using revised formulae. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use

*Perhaps the newer formula for calculated free T validated in multiple laboratories [65], will become generally available, correlate with free T by equilibrium dialysis, and demonstrate improved correlation with clinical symptoms and therapeutic responsiveness. If all these prove to be true, then this formula to calculate free T may be a justified replacement for free T measurement by the equilibrium dialysis methodology

What's Coming? Accurate measurement of total and free testosterone levels for the diagnosis of androgen disorders

Accurate measurement of total and free testosterone levels for the diagnosis of androgen disorders (7/2022) Ezgi Caliskan Guzelce, MD, Clinical/ Research Fellow, Francesca Galbiati, MD, Fellow, Anna L. Goldman, MD, Assistant Professor of Medicine, Arijeet K. Gattu, MD, Fellow, Shehzad Basaria...

www.excelmale.com

You are such a tease @madman. Stop torturing us.

 

[tareload]

If you want to use/rely on the calculated methods then go F**KING NUTS!

Let's go crazy
Let's get nuts
Let's look for the purple banana
'Til they put us in the truck, let's go!

We're all excited
But we don't know why
Maybe it's 'cause
We're all gonna die

And when we do (when we do)
What's it all for (what's it all for)
You better live now
Before the grim reaper come knocking on your door

 

[Cyclingislife]

Are you using IM shots or subcutaneous? I notice subq does not give you the same boost as IM. Why are you doing daily shots? With a normal SHBG you would probably do better on EOD or 2 or 3x per week. Also, I use Quest through discounted labs with the same test & I notice I only feel good with FT above 200. I’ve tested trough and the day after my shot. This shows me my highest & lowest level. I’m on EOD 25mg, IM shots but I have lower shbg around 20.

 

[tropicaldaze1950]

To me, always, the questions are; how do you feel, physically/mentally and how do you sexually function? Numbers are just numbers. They can look great or amazing and you feel miserable or you can't get an erection to save your life. Don't get lost in the numbers or obsess over them.

 

[drpub2112]

Are you using IM shots or subcutaneous? I notice subq does not give you the same boost as IM. Why are you doing daily shots? With a normal SHBG you would probably do better on EOD or 2 or 3x per week. Also, I use Quest through discounted labs with the same test & I notice I only feel good with FT above 200. I’ve tested trough and the day after my shot. This shows me my highest & lowest level. I’m on EOD 25mg, IM shots but I have lower shbg around 20.

Hey, thanks for the info! I'm still very new to all of it so it's not like I've had done a lot of experimenting with the protocol. I have done lots of research prior to starting TRT though and for now I'm buying into the concept that daily injections more closely mimic a natural rhythm. I know a lot of people do great with the 2-3 d/wk and EOD protocols. Also, since I'm prone to gyno, I want to start out doing everything I can to prevent E2 spikes or the need for an AI.

I've calculated that it would probably only take an adjustment of ~2-4mg/d to my dose to get my fT into that ~25 ng/dL (250 pg/ml) area that people often cite as being where they feel better. I've been sick with low T symptoms for many years, so I'm definitely interested in achieving a therapeutic dose. But at the same time, I know it can take a long time to improve and I don't want to get too zealous too fast.

All lab tests and fT calculations always point to my fT percentage being very close to 2.2% with my SHGB level. That's the thing they all agree on, even if the reference ranges vary. So from now on, as long as my SHGB doesn't change, I'm just going to assume my fT is ~2.2% of my Total every time. I feel like it's the most educated guess I can make at this point.

So, at 2.2%, 1000 ng/dL will yield a fT of 22 ng/dL. Ultimately, I think that's going to be my target area, since my current protocol isn't really making me feel better yet.

Thanks for the reply! How is your HDL? So far, that's the only marker of mine that has really changed. It dropped to 39 from 50. Range is >=40.

 

[drpub2112]

With a robust TT 756 ng/dL and normal SHBG 30 nmol/L, you can rest assured that your FT level is healthy.

Put money on it if you had your FT tested using Labcorp's TT (LC/MS-MS) with FT (Equilibrium Ultrafiltration) your FT would be near the top-end of the assay reference range 5.00-21.00ng/dL.

070038: Testosterone, Free, Equilibrium Ultrafiltration With Total Testosterone, LC/MS-MS | Labcorp

Labcorp test details for Testosterone, Free, Equilibrium Ultrafiltration With Total Testosterone, LC/MS-MS

www.labcorp.com

post #35

Could this be low E2?

I don't know what to make of these results. I've got crazy high total and E2, with average free. I think I can rule out my protocol having anything to do with my joint pain, so that's a positive. And like I had said, sexually I've been good, which was my whole reason for trt in the first place...

www.excelmale.com

My reply:

For the time being stick to testing your FT using Equilibrium Dialysis or Ultrafiltration, especially in cases of ALTERED SHBG!

Test using the same lab/same assay (most accurate).

Compare your blood work using the same lab/same assay (most accurate).

Forget using/relying upon the calculated methods in cases of altered SHBG until this S**TSHOW comes to an end which will be soon enough.

If you want to use/rely on the calculated methods then go F**KING NUTS!

*Currently, the CDC is developing a harmonized method for free T based on calculated free T using REVISED FORMULAE. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use

Now, why the F**K would they go and do that?



Key Points:

* Limitations of using free testosterone by equilibrium dialysis and calculated free testosterone concentrations in practice are the lack of assay standardization, an accuracy-based quality control program, and a harmonized reference range. Until these limitations are addressed, free testosterone by equilibrium dialysis and calculated free testosterone should use reference ranges established by individual laboratories or their specific assay method

*Assays that are standardized are designed to provide accurate results, traceable to “true” value-assigned certified reference materials and gold-standard reference methods. Results obtained using standardized methods can be compared across assays, institutions, populations, and past and future test results, thereby improving diagnosis, treatment, and outcomes of patients




The Need to Harmonize Clinical Laboratory Test Results-----

Laboratory test results are a critical component of patient care. These values help physicians diagnose disease and are critical to developing clinical guidelines that direct treatment options and are instrumental in ongoing efforts to improve and measure the quality of patient care. Most tests report a numeric value for healthcare providers to interpret and the range of numbers reported for a test for a certain condition may vary depending on the method used

Different test methods, however, may report different numeric values for the same condition. Although these test results may be accurate within the context of its own method, this variation can create confusion for physicians and patients. Clinical laboratory test results need to be harmonized so that healthcare providers and the public receive the same numeric result regardless of the method or instrument used or the setting where it was performed

CDC STANDARDIZED TOTAL T and ESTRADIOL ASSAYS and soon to be FREE TESTOSTERONE!

How the CDC Clinical Standardization Programs Are Improving Hormone Tests - AACC.org WHAT PROGRESS HAS CDC MADE WITH STANDARDIZING TOTAL TESTOSTERONE AND ESTRADIOL TESTS? Since HoSt began in 2010, CDC has had more than 350 participants in 15 countries. Participants have shown measurable...

www.excelmale.com

*Measuring FT is technically challenging and shows high variability. The CDC clinical standardization program is developing a high throughput method using the gold-standard equilibrium dialysis (ED) procedure with isotope dilution ultra-high-performance liquid chromatography-tandem mass spectrometry (ID-UHPLC-MS/MS)

This has been done now!

@Nelson Vergel

You heard it here first only on Excel (dropping the thread soon)!

CDC has developed a new higher-order reference method with high throughput FT ED UHPLC-MS/MS.

The method was used to evaluate the agreement between measured and calculated (cFTV).

N=45

The data in one of the slides show that a majority of the calculated values overestimated FT concentration compared to measured values (new higher-order reference method with high throughput ED UHPLC-MS/MS).

The mean bias is roughly 35% and a higher bias (upwards of 60%) was seen in the samples with low FT concentrations.


*The CDC ED-UPLC/MS/MS FT high-throughput method shows sufficient accuracy, precision, and sensitivity and is suitable for routine FT measurements in patient care and research settings

*The CDC ED-UPLC/MS/MS FT method can provide more accurate FT estimations compared to cFT by Vermeulen formula

CDC Hormone Standardization Program (CDC HoSt) Certified Free Testosterone Procedures is coming!

www.excelmale.com

View attachment 25106
View attachment 25105
View attachment 25107
View attachment 25108

What to Measure: Testosterone or Free Testosterone?

What to Measure: Testosterone or Free Testosterone? (2021) Christina Wang and Ronald Swerdloff 1.1 Why Serum Testosterone Is Necessary for the Diagnosis of Testosterone Deficiency? Low serum testosterone (T) levels in adult men can lead to significant clinical symptoms and signs of...

www.excelmale.com

*The binding of T to SHBG is complex, which results in many different methods that directly measure or calculate free T. Some of these methods do not measure the free fraction of T and some formulae may provide less accurate results [40]

*Recent evidence suggests that the law of mass action formula which is based on the assumption that two T molecules bind to two binding sites on the SHBG with similar binding affinity may be incorrect. And further argues that the binding of T to SHBG may be a multistep, dynamic process with complex allosteric characteristics [65]. Based on this new model, investigators used a new formula to calculate free T in younger men in the Framingham Heart Study and showed that the newly calculated values were similar to those measured by equilibrium dialysis. They further verified that the calculated free T values had clinical diagnostic validity using data from the European Male Aging Study

*Currently, the CDC is developing a harmonized method for free T based on calculated free T using revised formulae. This may bring the measurement of free T to a referable standard in clinical laboratories and common reference intervals that all clinicians can use

*Perhaps the newer formula for calculated free T validated in multiple laboratories [65], will become generally available, correlate with free T by equilibrium dialysis, and demonstrate improved correlation with clinical symptoms and therapeutic responsiveness. If all these prove to be true, then this formula to calculate free T may be a justified replacement for free T measurement by the equilibrium dialysis methodology

What's Coming? Accurate measurement of total and free testosterone levels for the diagnosis of androgen disorders

Accurate measurement of total and free testosterone levels for the diagnosis of androgen disorders (7/2022) Ezgi Caliskan Guzelce, MD, Clinical/ Research Fellow, Francesca Galbiati, MD, Fellow, Anna L. Goldman, MD, Assistant Professor of Medicine, Arijeet K. Gattu, MD, Fellow, Shehzad Basaria...

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The best part in the study was where they said "7/2022".