AGE SPECIFIC CALCULATED FREE TESTOSTERONE RANGES IN ADULT MEN

Buy Lab Tests Online

madman

Super Moderator
INTRODUCTION AND OBJECTIVE

Measurement of free testosterone (FT) levels can be an important step in the evaluation of men with suspected testosterone deficiency. While it is well known that FT levels decline with age, its clinical utility is limited due to the lack of data on age specific reference ranges. This study aimed to provide age specific reference ranges for FT to assist in the evaluation of men with suspected testosterone deficiency.


METHODS

The 2013-2016 National Health and Nutrition Examination Survey was used to collect data on a nationally representative sample of men in the United States. Men were included in the analysis if they were 20 years old and had total testosterone labs available that were drawn in the morning (between 6 and 10 a.m.). Men were excluded from the study if they had a BMI>30, serum creatinine>1.5, AST or ALT>1.5 times the upper limit of normal, history of diabetes mellitus, testicular cancer, thyroid disease, or were on hormonal medications. FT levels were calculated using total testosterone, sex hormone binding globulin levels and albumin. Age specific ranges were separated into 10-year intervals, with exception of the final interval being all men 80 years old.


RESULTS

1,147 men were included in our final cohort. For each age category, we observed large differences in individual FT levels (Table 1). The highest levels of FT were observed in the youngest category (mean 114.3 pg/mL) and declined on average 12.7% each decade to a mean of 45.8 pg/mL in men 80 years old. The largest decline in average FT was observed from 20s to 30s with an average decline of 16.9% (Figure 1).


CONCLUSIONS


To our knowledge, this is the first study to evaluate age specific calculated FT ranges in adult men. There is a consistent decline in FT in adult men with peak FT concentrations in their 20s. The large range of FT levels within each category indicates the need for a prospective study to identify factors that contribute to declining FT levels and to aid in the clinical diagnosis of testosterone deficiency.
 

Attachments

  • dokter-et-al-2024-pd28-05-age-specific-calculated-free-testosterone-ranges-in-adult-men.pdf
    204.3 KB · Views: 238
Defy Medical TRT clinic doctor
Distribution Percentiles of Free Testosterone (pg/mL)

Screenshot (34832).png
 
My results for Free T were 1.16 ng/dl. I am 70. Anyone know where this would place me? My total testosterone is always at the top of the range and my free is always mid range. I am trying boron supplementation to raise it.
 
Even after accounting for falling testosterone levels over the years, these numbers seem low compared to what might be expected from the Vermeulen calculation. I wonder if they are applying a normalization factor to better match results from equilibrium dialysis? Or are they using some other calculation?
 
My Free T is 38.6 pg/ml and that is at the VERY BOTTOM of the range for 70-79 age.
Looks Like 70 pg/ml is Mid-Range.
LabCorp says 38.6 pg/ml is High out of Range.
 
I wouldn't compare any free testosterone values to this study until it's clearer how they got their numbers.

If you use the Vermeulen calculation then you can compare yourself to a range for healthy young men of about 70-230 pg/mL (7-23 ng/dL).
 
I wouldn't compare any free testosterone values to this study until it's clearer how they got their numbers.

If you use the Vermeulen calculation then you can compare yourself to a range for healthy young men of about 70-230 pg/mL (7-23 ng/dL).

Even then we need to wait on harmonized FT reference ranges based on a standardized FT assay (ED-LC/MS/MS).

Similar to what was done for harmonized TT.

*Assays that are standardized are designed to provide accurate results, traceable to “true” value-assigned certified reference materials and gold-standard reference methods.

The CDC has been working hard on this and it is not too far off now!

Soon enough we will have a CDC Hormone Standardization Program (CDC HoSt) Certified Free Testosterone Procedure and a harmonized reference range for free testosterone!


1713723546039.png





Something to keep in mind when it comes to using/relying upon the calculated FT methods!

*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





Take home points:

*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

* 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
 
My results for Free T were 1.16 ng/dl. I am 70. Anyone know where this would place me? My total testosterone is always at the top of the range and my free is always mid range. I am trying boron supplementation to raise it.

You must have meant 11.6 ng/dL as there is no way your FT is 1.16 ng/dL with a top-end TT.

If your TT is at the top-end of the reference range even with highish/high let alone absurdly high SHBG your FT would not be that low!

What method (direct immunoassay, ED, UF, calculated) was used to test your FT and what was the reference range.

As I have stated numerous times on the forum when it comes to testing free testosterone you would need to use/rely upon the most accurate assays such as the gold standard Equilibrium Dialysis or Equilibrium Ultrafiltration (next best) especially in cases of altered SHBG to know where your FT truly sits.

If you do not have access to such (highly doubtful if you live in the US) then you would need to use/rely upon the linear law-of-mass action cFTV

You can easily find out where your FT sits using the linear law-of-mass action cFTV which is available online for free.

Plug in your TT, SHBG and Albumin to see where your FT sits.


Keep in mind as of now cFTV tends to overestimate slightly when compared to a standardized gold standard ED assay.

Also keep in mind that Quests /Labcorps let alone any of the other labs Equilibrium Dialysis or Equilibrium Ultrafiltration assays in the US or any other country are not standardized!

Top it of that there is no harmonized reference range to boot!
 
You must have meant 11.6 ng/dL as there is no way your FT is 1.16 ng/dL with a top-end TT.

If your TT is at the top-end of the reference range even with highish/high let alone absurdly high SHBG your FT would not be that low!

What method (direct immunoassay, ED, UF, calculated) was used to test your FT and what was the reference range.

As I have stated numerous times on the forum when it comes to testing free testosterone you would need to use/rely upon the most accurate assays such as the gold standard Equilibrium Dialysis or Equilibrium Ultrafiltration (next best) especially in cases of altered SHBG to know where your FT truly sits.

If you do not have access to such (highly doubtful if you live in the US) then you would need to use/rely upon the linear law-of-mass action cFTV

You can easily find out where your cFT sits using the linear law-of-mass action cFTV which is available online for free.

Plug in your TT, SHBG and Albumin to see where your FT sits.


Keep in mind as of now cFTV tends to overestimate slightly when compared to a standardized gold standard ED assay.

Also keep in mind that Quests /Labcorps let alone any of the other labs Equilibrium Dialysis or Equilibrium Ultrafiltration assays in the US or any other country are not standardized!

Top it of that there is no harmonized reference range to boot!
 

Attachments

  • 1713736405137.png
    1713736405137.png
    415.5 KB · Views: 145
  • IMG_0464.png
    IMG_0464.png
    415.5 KB · Views: 137
@Mountain Man

Had to be more thorough here!

Your FT was tested using the known to be inaccurate direct analogue radioimmunoassay (RIA) reference range Male: 20-50 years 0.87-5.47 ng/dL.

Never seen this reference range for FT as most are using/relying upon Labcorp direct analog enzyme immunoassay (EIA) reference range Male: 6.6 - 26.5 pg/mL (low/high-end depending on age) or Quests Equilibrium Dialysis reference range Male: 35-155 pg/mL or cFTV reference range Male: 18-69 yrs 46.0-224.0 pg/mL.

Labcorp Equilibrium Ultrafiltration is another commonly used FT assay with reference range Male Adults: 5.00-21.00 ng/dL.

What is your TT and SHBG?



 
@Mountain Man

No one should be using/relying upon the known to be inaccurate direct analog immunoassays especially in cases of altered SHBG.

Again when it comes to testing free testosterone you would need to use/rely upon the most accurate assays such as the gold standard Equilibrium Dialysis or Equilibrium Ultrafiltration (next best) especially in cases of altered SHBG to know where your FT truly sits.

If you do not have access to the most accurate assays then you would need to use/rely upon the linear law-of-mass action cFTV

As I stated previously you can easily find out where your FT sits using the linear law-of-mass action cFTV which is available online for free.

Plug in your TT, SHBG and Albumin to see where your FT sits.


Free & Bioavailable Testosterone calculator
 
Confused AF. This is low for a 70 year old, is that correct?
No, a cFTV (calculated free testosterone by Vermeulen) of 17.2 ng/dL is above average for healthy young men. Average for them is around 15 ng/dL. Or at least it was some decades back.

As I said above:

If you use the Vermeulen calculation then you can compare yourself to a range for healthy young men of about 70-230 pg/mL (7-23 ng/dL).
 
Confused AF. This is low for a 70 year old, is that correct?

Not a chance!

Most healthy young males would be hitting a cFTV 13-15 ng/dL and this is at peak (short-lived).

With a very high TT 970 ng/dL, high SHBG 53 nmol/L and Albumin 4.3 g/dL (default) your FT 17.2 ng/dL would be healthy and far from lowish/low.

Even then the shitkicker here is if this is your trough FT (lowest point) before your next injection then your peak TT, FT and estradiol will be even higher even to the point of absurdly high depending on your injection frequency.

From what I recall you have been on testosterone therapy for 6-7 years using a once weekly protocol starting out at 100 mg T/week and eventually over the years bumping it up to 140-150 mg T/week, no AI or hCG.

Your SHBG has always been on the higher end 50s.

You have never deviated from the once weekly injections.

Now if these labs were done at the true trough (7 days post-injection) and you are hitting a healthy trough FT 17.2 ng/dL then it is a given your peak TT, FT and estradiol will be much higher!

What is your current protocol (dose of T/injection frequency) and how many days post-injection were your labs done?

This is critical as we always want to have blood work done at the true trough (lowest point) before your next injection.


1713796959258.png
 
Not a chance!

Most healthy young males would be hitting a cFTV 13-15 ng/dL and this is at peak (short-lived).

With a very high TT 970 ng/dL, high SHBG 53 nmol/L and Albumin 4.3 g/dL (default) your FT 17.2 ng/dL would be healthy and far from lowish/low.

Even then the shitkicker here is if this is your trough FT (lowest point) before your next injection then your peak TT, FT and estradiol will be even higher even to the point of absurdly high depending on your injection frequency.

From what I recall you have been on testosterone therapy for 6-7 years using a once weekly protocol starting out at 100 mg T/week and eventually over the years bumping it up to 140-150 mg T/week, no AI or hCG.

Your SHBG has always been on the higher end 50s.

You have never deviated from the once weekly injections.

Now if these labs were done at the true trough (7 days post-injection) and you are hitting a healthy trough FT 17.2 ng/dL then it is a given your peak TT, FT and estradiol will be much higher!

What is your current protocol (dose of T/injection frequency) and how many days post-injection were your labs done?

This is critical as we always want to have blood work done at the true trough (lowest point) before your next injection.


View attachment 43663
Wow! You’re good. I should be sending you my copayment! Currently inject once per week, 130-140 mg. This was at the trough.
 
Last edited:
Beyond Testosterone Book by Nelson Vergel
Wow! You’re good. I should be sending you my copayment! Currently inject once per week, 130-140 mg. This was at the trough.

If you have always felt great overall on such protocol (130-140 mg T/week) then I would not change a thing!

Most of those clueless sheep with that more T is better mentality polluting the so called men's health forums would tell you that your trough cFTV 17.2 ng/dL is too low and that you should be aiming for that magical trough FT 30-60 ng/dL LMFAO!

Critical that one pays attention to their injection frequency/trough FT as again there is a world of difference in one hitting a very high trough FT 30 ng/dL injecting once weekly vs daily or EOD!

Again you are hitting a healthy trough cFTV 17.2 ng/dL and this is 7 days post-injection which means that your peak (12-24 hrs) post-injection TT/FT will be very high let alone during the first 2-3 days every week!

You are hitting a high-end trough TT 970 ng/dL and more importantly a healthy trough FT.

Bet your peak TT is somewhere in the 1600-1800 ng/dL range with a very high FT!

If you were truly convinced that your trough cFTV 17.2 ng/dL level was not high enough let alone you did not feel as great come weeks end (trough) then I would say the most sensible move would be to split your weekly dose and inject more frequently to clip the peak--->trough which would soften your peak and bring up your trough and even then you could most likely get away with decreasing your dose slightly while still achieving a high-end trough FT.

Again those that are clueless would have been telling you to increase your dose and bring up your trough FT LOL!

Hope you understand how critical it is to have your FT tested using accurate assays (Equilibrium Dialysis or Ultrafiltration) especially in cases of altered SHBG.

As I stated previously if you do not have access to such highly doubtful if you live in the US then you should be using/relying upon the linear law-of-mass action cFTV.
 
Buy Lab Tests Online
Defy Medical TRT clinic

Sponsors

bodybuilder test discounted labs
cheap enclomiphene
TRT in UK Balance my hormones
Discounted Labs
Testosterone Doctor Near Me
Testosterone books nelson vergel
Register on ExcelMale.com
Trimix HCG Offer Excelmale
BUY HCG CIALIS

Online statistics

Members online
1
Guests online
6
Total visitors
7

Latest posts

Top