Trying to conduct a study with the members here at T-nation…
Please post your Tru-T calculated Free Testosterone and your Equilibrium Dialysis measured Free Testosterone. A study I have read and posted on shows that “calculated” Free T is largely over-estimated. I am wondering if many think they are optimal Free T wise but in reality could still be sub-optimal when looking at actual measured Free T.
Post in this format…
ED measure Free T 5.3 ng/dl
Tru-T calculated Free T 11.63 ng/dl
Thank you for contributing… If your 27.84 pg/ml value is from Lab corp then this number is actually meant to be represented as ng/dl… seems to be a typo on their end and has been discussed before. As for which one is more accurate all of the studies I have read, say that “calculated” Free T is highly over estimated. Please read the below study and the excerpts from another study testing the same algorithms that Tru-T uses.
“Of the three methods we evaluated in this study, cFT-V, albeit systematically overestimating FT , most robustly approximated directly measured FT in samples representative of a broad range of T and SHBG levels“
“cFT-Z appears far off target relative to the results of direct ED in this study as well as compared with a substantial body of published data obtained with a variety of ED- or UF-based methods. Although cFT-L performs well in the midrange levels of serum T and SHBG, the dependence of its accuracy on T and SHBG levels has clinical implications ( e.g. , underestimation by cFT-L of FT at low SHBG concentrations could impair the ability to detect hyperandrogenism“
These excerpts can be found at
I am trying to draw a link to the possibility that some… not all… might not be experiencing symptom relief due to the fact that they think their Free T is midrange while relying on the calcuated value when in reality their actual measured Free T is much lower… on the low-normal side of the range. This could explain why some dance in circles looking for symptom relief when their Free T is “optimal”.
Someones Tru-T Free T is calculated at 22ng/dl looks good right (mid-range upper).
However their actual free T is 13ng/dl… (lower side of the range)
TT = 417 ng/dL
FT = 14.9 (6.8-21.5)
SHBG = 22
Tru-T = 13.83 ng/dL (16-31 ng/dL)
Albumin = 4.5
TT = 697 ng/dL
FT 29.6 (6.8-21.5)
SHBG = 16
Tru-T = 24.37 ng/dL (16-31 ng/dL)
These results actually show directly measured (Equilibrium Dialysis) FT higher than the Tru-T calculation method. I see a lot of men on these forums experiencing low testosterone with FT around or lower than 15 pg/mL, I don’t normally see guys complain of much above 15 pg/mL.
Dr. Abraham Morgentaler has stated men <15 pg/mL will likely show benefit on TRT.
Very interesting to see your values coming back the opposite. I am working on pulling data from over 10 sets of labs right now… almost all are significantly higher when calculated. Thank you for contributing. Once the sample size is large enough I will create a nice visual and start to statistically draw conclusions and correlations.
I am wondering if the lower the SHBG… the lower the accuracy of this prediction. Only a larger sample size will tell. You could be a outlier @systemlord perhaps your SHBG is extremely “less sticky” and that is why your Free T is higher and you feel best on a strict ED protocol… Just a thought.
When I was on my once weekly protocol (75mg), 3 days after my injection I scored a 550 ng/dL, a day before my next injection I scored a 440 ng/dL. It’s hard to compare like this because you could take the same blood sample, split it up into four samples and get four different results.
These above numbers no one would guess I have low SHBG is there didn’t know otherwise. After 15 weeks I started noticing a huge crash days after my shot. One could say I’m extremely sensitive to hormone fluctuations. Going from 550 ->440 is devastating.
Agreed, im very interested to see all of the labs that will be hopefully posted in this thread. I think it is a great opportunity to explore what we accept as “normal” methods for basing Free T. This in my opinion, is exactly how things are revolutionized. Today we might all believe in calculators, then a study is done, and tomorrow we might believe in true measurements… only way to tell is through the participation and contribution of the members here. We already know doctors are out when it comes to brushing up on their studies.
What is your pertinent past medical history? Any major surgeries or medical treatments over the course of your life time thus far? I double as a paramedic/firefighter and medicine has always fascinated me. Wishing I could go back in time and go to med school lol.
Did you notice here, how the lower your SHBG became… the further the gap between measured and calculated values? Very interesting. Almost as if the calculators take little account for individual SHBG responses/sensitivity
"underestimation by cFT-L of FT at low SHBG concentrations could impair the ability to detect hyperandrogenism“
Read this line above… calculators when given low SHBG will actually understimate… not over estimate. Which is exactly seen in your case.
So this could be two fold. Calculators under estimate when given lower SHBG and over estimate when SHBG is normal/higher range. Again more samples are needed to confirm but definitely holds true for you and the other labs I have seen.
No surgeries, I was diagnosed with Turrets Syndrome at 7 years old for which I was on klonopin for 30 years which when I withdrew the medicine, it caused HPTA dysfunction. Having Turrets syndrome may be responsible for my lifelong hypersexuality and sensitivity to hormone fluctuations because my central nervous system is primed to be very sensitive.
I over respond to all medicines, some foods and also when testosterone is 400, explosive energy for a guy my age. This might explain why I have been able to function with testosterone below 100 ng/dL for 7 months.
I wonder if your brain ever re-wired your neural pathways after such extensive klonopin use especially at the age where these connections are forming… You could still suffer Dopamine deficits and in theory your brain is still adapting. Maybe why you are so sensitive to fluctuations. But again just another thought and Dopamine/hormonal levels is a definitely a topic for another time. Thank you for taking the time to share your information. Would you describe yourself as a person who feels empathy?
This coincides with what I am seeing as well, that is why it is extremely important to have a accurate free T reading. A calulated Free T of 22 ng/dl could really mean a ED measured Free T value <15… explaining the lack of symptom relief for some.
TT 1995 ng/dl
Free T 13.3 ng/dl
Tru T calculated 56.71 ng/dl
SHBG 146 (Not a typo)
In this case just imagine if the individual accepted his 56.71 value and had no measured free T value? He would have been extremely confused as to why he had low T symptoms. Obviously this was not the case and his free T was <15 ng/dl.
So far the higher the SHBG the greater the over estimation, and the lower the SHBG the exact opposite. This has been reported numerous times throughout various studies. I encourage everyone looking for symptom relief to make sure they are not relying soley on calculated values.
Soon hopefully I will have statistical values for SHBG and calculated Free T.