TT vs FT which is more important and why?

[robs2nd75]

Many physicians will test for both but some neglect to test for Free T. If FT is a measure of what our bodies actually use why are physicians (seemingly) placing more importance on TT? Should men be more concerned with their FT or TT and why?

 

[Gene Devine]

We need to be concerned with both for many reasons than I can list here.

Total Testosterone is important as we want to see how much in aggregate the body is producing in serum. This is especially important as it relates to transport hormones like SHBG, Albumin and Estrogen conversion.

Free Testosterone is critical in that it tells us how much of the Total Testosterone is available for the body to use. In other words, the stuff that makes the magic!

Doctor's who don't test for Free T are the ones who simply are not trained correctly unless they are calculating Free T from other labs (and this I doubt most GPs or Endos know how to do this correctly).

Just look at how many GPs and Endos use TSH only to evaluate Thyroid health...and for those that are trained correctly know that TSH is a very very poor marker for evaluating Thyroid health.

 

[Nelson Vergel]

The main reasons why free testosterone is not used for diagnosis (even though I think it should be) are:

1- Insurance companies only go by total testosterone (usually anything below 350 ng/dL is considered hypogonadism when 4 items of this questionnaire are met:https://www.excelmale.com/blood-tests-needed-before-and-during-testosterone-replacement-therapy/ )

2- Most studies have not used free testosterone as main variable in analysis.

3- Free testosterone blood testing is more expensive than total testosterone.

4- Free testosterone is usually 2-4% of total testosterone. I have only seen very few people not falling in that range.

Here is an example of a study that found free testosterone is better for diagnosis of hypogonadism in HIV+ men:

http://www.aidsmeds.com/articles/hiv_hypogonadism_testosterone_1667_22880.shtml