Does anyone know what is the most accurate test to measure free testosterone of these two?

[T4 Life]

Testosterone, Free, LC/MS/MS

Methodology

Calculation (CALC) • Immunochemiluminescence Assay (ICMA) • Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS) • Spectrophotometric http://www.questdiagnostics.com/testcenter/TestDetail.action?ntc=90572

or

Testosterone, Free (Dialysis) and Total LC/MS/MS
Includes

Total Testosterone, Free Testosterone (calculated)
Methodology

Calculation (CALC) • Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS) • Tracer Equilibrium Dialysis
http://www.questdiagnostics.com/testcenter/TestDetail.action?ntc=36170

 

[Nelson Vergel]

The first on actually measures free T by liquid chromatography but does not tell you total T.

The second one measures total T by liquid chromatography and calculates free T (from SHBG and albumin)

I would use one that measures both free and total T by Liquid Chromatography/Mass spectrometry.

http://www.discountedlabs.com/testosterone-free-total/