Bioavailable or free test

[augor]

Hey guys
I had an appointment with an endo this week.
She right off told me that the tests my family doc sent me for, total test, free test, were not the right ones.
She tells me free test is not the important one, this goes against most if what I've read or heard.
She says the only way to get the most accurate number is doing the bioavailable testosterone test.

Any thoughts?

 

[hannes joubert]

Unless I am misunderstanding the semantics, I thought free test was bio-available test?

 

[augor]

There a

 

[augor]

Apparently there is another one . Here in Canada at least it's referred to as bioavailable testosterone and that test we have to pay for

 

[hannes joubert]

Unfortunately there does not seem to be a standard between the various countries, even in the measuring protocols and the ranges...

Good luck Bro, hope someone has an answer for you...

 

[Zyglamail]

Testosterone and dihydrotestosterone (DHT) circulate in plasma unbound, bound to specific plasma proteins (sex hormone-binding globulin SHBG) and weakly bound to nonspecific proteins such as albumin. The SHBG-bound fraction is biologically inactive because of the high binding affinity of SHBG for testosterone. Free testosterone measures the free fraction, bioavailable testosterone includes free plus weakly bound to albumin.

I dont know that I agree free test isnt a valid number to work with however.

 

[augor]

Would u say a test for bio available test is more accurate to judge ones levels then a standard free testosterone test?
This is what endo was saying, that original free and total test results were garbage, and that only bio available tells the real story of how well I am producing

 

[Zyglamail]

Would u say a test for bio available test is more accurate to judge ones levels then a standard free testosterone test?
This is what endo was saying, that original free and total test results were garbage, and that only bio available tells the real story of how well I am producing

Free test is just that, free test, that is easily bound whereas bioavailable is free test plus weakly bound test. Im assuming the weakly bound test still has the ability to bind to the androgen receptor to some degree. That being said, just how much of the weakly bound test is truly viable? I dont think bioavailable would be more accurate unless its affinity to the andro receptor can accurately be caclulated.

 

[augor]

This what I was wondering, as my endo , Who clearly has a bit of a god complex.
Was adamant that bio was more accurate then free.
She even said free test wasn't as important then total test.
Either way , she's fired , and my family doc is ok with continuing our current course of action, that is working.
And at another date he will refer me to another endo.
It wasn't till I hit this condition that I truly had more respect for the US does things with health care.
Sure in canada, we don't have to worry about paying for so many services (allthough I'm sure we are paying if u know what I mean)
But at least in the US if u want to see an endo next week, u can make it happen.
For me , it's allways gonna be a 3 month wait.
Hell even the one I just seen won't see me again till may 30th!
So the road to getting better in canada is an even longer one.
But at this point at 125mg a week , I feel I'm pretty damn close to the does that makes me whole again.
Starting in April, I plan on doing a 10 week cycle of just more test.

Thanx for all replies

 

[theemperor]

Free test is just that, free test, that is easily bound whereas bioavailable is free test plus weakly bound test. Im assuming the weakly bound test still has the ability to bind to the androgen receptor to some degree. That being said, just how much of the weakly bound test is truly viable? I dont think bioavailable would be more accurate unless its affinity to the andro receptor can accurately be caclulated.

I agree 100% Zyg,

That is a very, very strong case you just stated, and I was thinking the same things along those lines.Free Test, has been noted by ALL HRT and the Doc I am at that is the most important. Its inactive, making it dormant in stage but once given higher concentrations and released, THAT is pivatal.

 

[XMAN.]

hope this help clear things up : link : Bioavailable Testosterone - Physician Overview

Bioavailable Testosterone - Physician Overview

Testosterone is present in the circulation both in protein bound (96%) and in non-protein bound ('free' or unbound) formats. In males, about 44% is bound to Sex Hormone Binding Globulin (SHBG), 50% to albumin and 2-3% 'free' (1).
Until recently it was believed that only the 'free' fraction of testosterone could be taken up by tissues and the protein-bound testosterone complex was inactive. It has now been demonstrated that the albumin bound fraction of testosterone readily dissociates and is absorbed up by the tissues along with the 'free' fraction. Together, these two fractions are referred to as the bioavailable testosterone (Bio-T) fraction.
Clinical Relevance of Bio-T
Whilst age related decreases in total testosterone are debated, studies have shown consistent reductions in bioavailable testosterone of up to 50% in elderly males (2). In some patients, pathologically low levels have been seen in association with declining libido and poor sexual performance. Diminished levels may also be a contributing factor to symptoms of andropause, the male equivalent of menopause. Recent studies have also associated decreased levels with depression in the elderly (3) as well as osteoporosis (4).
In females, increased levels have been associated with some cases of hirsutism. Reduced levels have been found in patients with osteoporosis (4).
Indications for ordering Bio-T
Total testosterone and 'free' testosterone assays have been traditionally ordered. Until further knowledge is gained on the assay, these tests should continue to be ordered, along with bioavailable testosterone.
Males:

• Suspected hypogonadism, as seen in a decline of libido or sexual performance
• Infertility
• Andropause ("male menopause")
• Osteoporosis

Females:

• Evaluation of hirsutism
• Osteoporosis

Sample requirements & Test Availability

• Samples should be collected before 10:00 a.m.
• Collect one full SST-tube; allow to clot for 30 minutes. Centrifuge, separate serum and freeze immediately. Sample must be transported to the laboratory frozen.
• This test may not be insured by provincial health plans but it may be covered by a patient's insurance plan.
• Please refer patient to a LifeLabs Patient Service Centre for collection.

Test Results
Results are available within 7-10 days.
References
Manni A, Pardrige WM, Cefalus W, Nisula BC, Bardin CW: Bioavailability of albumin-bound testosterone. J Clin Endocrinol Metab 61:705, 1985.
Ferrini RL and Barrett-Connor E: Sex hormones and age. Am J Epidemiol 147(8):750-4, 1998.

Barrett-Connor E, Von Muhlen DG and Kritz-Silverstein D. Bioavailable testosterone and depressed mood in older men: the Rancho Bernardo study. J Clin Endocrinol Metab, 84(2): 573-7, 1999.

Greendale GA, Edelstein S, Barrett-Connor E, Endogenous sex steroids and bone mineral density in older women and men: the Rancho Bernardo Study. J Bone Miner Res 12(11): 1833-43, 1997.