chilln
01-26-2009, 05:36 AM
Hello all.
Here's some good news, recently discovered by Investmentbanker.
Labcorp now have a bioavailable testosterone test, number 143255, and here's the summary:
https://www.labcorp.com/datasets/labcorp/html/chapter/mono/sr016000.htm
[[ chilln edit: you now need to put 143255 into the test number field at the above page - labcorp have modified their URLs to be dynamically generated ]]
It uses direct measurement, ie: ammonium sulfate precipitation, and radioassay.
I assume that calcs comparing the components of SHBG and albumin are not used, or else they would be written in the summary.
Quests current test for bioavailable testosterone, number 14966X, uses calcs, from total testosterone, albumin, SHBG, and some sort of empirical adjustment which is the function of the algorithm itself.
Quest claimed they compared their calcs for bioavailable testosterone against ammonium sulfate precipitation, and the results were "adequately" accurate when total testosterone is in the higher ranges.
That means that Quest's test isn't optimum when total testosterone is in the lower ranges.
I have always assumed Quest used calcs because the ammonium sulfate precipitation test must have been more expensive to perform reliably.
Of course we still don't know how accurately Labcorp are measuring the ammonium sulfate precipitates. So Labcorp's test may still be less accurate than Quest's calcs.
###
The most important thing is that this will raise the bar on bioavailable testosterone testing, which makes us the winners. If Labcorp's methodology turns out to be accurate, and if Dr Crisler endorses it, then we may be asked to make the switch, or we may be asked to go with either.
Choice is a wonderful thing.
Thanks Labcorp.
Here's some good news, recently discovered by Investmentbanker.
Labcorp now have a bioavailable testosterone test, number 143255, and here's the summary:
https://www.labcorp.com/datasets/labcorp/html/chapter/mono/sr016000.htm
[[ chilln edit: you now need to put 143255 into the test number field at the above page - labcorp have modified their URLs to be dynamically generated ]]
It uses direct measurement, ie: ammonium sulfate precipitation, and radioassay.
I assume that calcs comparing the components of SHBG and albumin are not used, or else they would be written in the summary.
Quests current test for bioavailable testosterone, number 14966X, uses calcs, from total testosterone, albumin, SHBG, and some sort of empirical adjustment which is the function of the algorithm itself.
Quest claimed they compared their calcs for bioavailable testosterone against ammonium sulfate precipitation, and the results were "adequately" accurate when total testosterone is in the higher ranges.
That means that Quest's test isn't optimum when total testosterone is in the lower ranges.
I have always assumed Quest used calcs because the ammonium sulfate precipitation test must have been more expensive to perform reliably.
Of course we still don't know how accurately Labcorp are measuring the ammonium sulfate precipitates. So Labcorp's test may still be less accurate than Quest's calcs.
###
The most important thing is that this will raise the bar on bioavailable testosterone testing, which makes us the winners. If Labcorp's methodology turns out to be accurate, and if Dr Crisler endorses it, then we may be asked to make the switch, or we may be asked to go with either.
Choice is a wonderful thing.
Thanks Labcorp.