Free T is important, what about Free DHT and Free Estradiol?

[ResearchIt]

Wikipedia says, "The relative binding affinity of various sex steroids for SHBG is dihydrotestosterone (DHT) > testosterone > androstenediol > estradiol > estrone. DHT binds to SHBG with about 5 times the affinity of testosterone and about 20 times the affinity of estradiol."

Why aren't there lab tests for Free DHT since it binds to SHBG even more so than T?

Knowing Free T is more useful than just knowing T. So wouldn't knowing Free DHT be more useful than just measuring DHT? Same with Estradiol to a lesser extent since it doesn't bind to SHBG as much?

Sorry, I probably should have posted this in the Blood Test discussion forum, but don't know how to move it now.

 

[Cataceous]

They're still expensive. Otherwise they would be used more often if they proved to be accurate.

504026: Dihydrotestosterone (DHT), Free, LC/MS/Dialysis | Labcorp

Labcorp test details for Dihydrotestosterone (DHT), Free, LC/MS/Dialysis

www.labcorp.com

$172 through Defy Medical

500649: Estradiol Free, Equilibrium Dialysis, With Total Estradiol, HPLC/MS-MS (Endocrine Sciences) | Labcorp

Labcorp test details for Estradiol Free, Equilibrium Dialysis, With Total Estradiol, HPLC/MS-MS (Endocrine Sciences)

www.labcorp.com

$100 through Defy Medical

There's a spreadsheet around that calculates various free hormone levels based on the measured totals. It uses the Multi-Ligand model.

 

[ResearchIt]

They're still expensive. Otherwise they would be used more often if they proved to be accurate.

When you say "if they proved to be accurate" do you mean these tests are not accurate, or they are accurate but just expensive?

Also, for Estradiol, would you rather have an Estradiol Sensitive or Estradiol Free lab done or both? Are you aware of any Estradiol Free Sensitive lab? Thanks!

 

[Cataceous]

I mean that because of their complexity these tests may require a lot of precise fiddling in order to be accurate. This introduces the possibility of errors and inaccurate results. I have found this to be true even with total estradiol tests. I do not rely on the sensitive estradiol test because for me it has been botched about a third of the time I've used it, returning results far removed from reality. No such problems with the standard test. The standard test is simply a few percent higher than the sensitive test when the latter is done right.

As far as I know there is no such thing as a non-sensitive free estradiol test. I assume the concentrations involved are two low for immunoassay techniques.

If it were reliably accurate and affordable I'd opt to know free estradiol over total estradiol. That would be more informative. Both LabCorp and Quest offer the test, e.g. the one mentioned above.

 

[ResearchIt]

Thanks very much, I appreciate the feedback!

 

[tareload]

As far as I know there is no such thing as a non-sensitive free estradiol test. I assume the concentrations involved are two low for immunoassay techniques.

From our other thread in case folks interested.

 

[ResearchIt]

It is very interesting to see the limitations on certain testing. Lots of great information in that other thread too, I am still reading through it all before replying