@Cataceous, are those ranges for what is considered normal in general 2 standard deviations on each side of the mean? Meaning 23ng/dL would be approximately the 98th percentile?
AGE SPECIFIC CALCULATED FREE TESTOSTERONE RANGES IN ADULT MEN
- Thread starter madman
- Start date
Yes. Here is one such study:
madman
Super Moderator
You are hitting a cFTV 17.2 ng/dL at the true trough (7 days post-injection).
Keep in mind as of now cFTV tends to overestimate slightly when compared against a state of the art/standardized ED assay.
Even then you would most likely still be hitting a trough FT 15 ng/dL (7 days post-injection).
Now think about how much higher your peak TT/FT (8-12 hrs post-injection) during the first 2-3 days every week would be!
The testing method used for FT was state-of-the-art direct ED method (ED LC-MS/MS)!
What percentile of healthy young men would even be hitting a peak not trough FT 17.1 ng/dL!
Age-stratified reference ranges for directly measured (ED LC-MS/MS) serum free testosterone in healthy men
Just to be clear up any confusion this is Fiers camps data for mFT reference ranges not the harmonized reference range being worked on by the CDC. *Serum samples were analyzed from healthy men participating in the SIBLOS/SIBEX and EMAS studies, both population-based cohort studies * mFT...
www.excelmale.com
We present 95% mFT age-stratified reference ranges
Age category (years) | Median mFT (ng/dl) | 95% mFT reference range (ng/dl) |
25-29 (n=148) | 10.3 | 5.6 - 17.1 |
30-39 (n=252) | 9.7 | 4.9 - 18.1 |
40-49 (n=207) | 8.0 | 4.3 - 13.5 |
50-59 (n=146) | 7.0 | 3.8 - 12.6 |
60-69 (n=114) | 5.9 | 3.3 - 11.9 |
*The gold-standard for the determination of FT levels is considered to be directly measured free testosterone (mFT) using equilibrium dialysis followed by mass spectrometry (ED LC-MS/MS). However, no widely accepted reference ranges are available for this clinical parameter. We established mFT reference ranges for healthy men aged 18 to 69 years
*Serum samples were analyzed from healthy men participating in the SIBLOS/SIBEX and EMAS studies, both population-based cohort studies
* mFT levels were measured in 867 men using ED LC-MS/MS as previously reported (1).
Reference: 1. Fiers T, Wu F, Moghetti P, Vanderschueren D, Lapauw B, Kaufman JM. Reassessing Free-Testosterone Calculation by Liquid Chromatography–Tandem Mass Spectrometry Direct Equilibrium Dialysis. J Clin Endocrinol Metab. 2018;103(6). doi:10.1210/jc.2017-02360
Reassessing Free-Testosterone Calculation by Liquid Chromatography–Tandem Mass Spectrometry Direct Equilibrium Dialysis
Reassessment of FT in women and men with state-of-the-art methodology confirms previously established FT percentages but highlights limitations of differen
academic.oup.com
In the current study, we used a state-of-the-art direct ED method to reassess FT in sets of representative serum samples. This method takes advantage of the ability of a highly sensitive and accurate measurement of T by liquid chromatography–tandem mass spectrometry (LC-MS/MS) to reliably measure the low FT concentration directly in the dialysate after ED. This more straightforward method avoids potential sources of inaccuracy in indirect ED, such as those resulting from tracer impurities or from measures to limit their impact (e.g., sample dilution). We then used the measured FT results to re-evaluate some characteristics of two more established and a more recently proposed calculations for estimation of FT.
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