Free Testosterone by Mass Spectrometry/Equilibrium Dialysis Build info

Synonyms

• TESTOSTERONE, FREE MS/EQ DIALYSIS
• TESTOSTERONE, FREE MS/EQ DIALYSIS
• TESTMS
• LAB11138

Short Name

TESTOSTERONE, FREE MS/EQ DIALYSIS

Procedure Master Number

LAB11138

Procedure ID

114664

Clinical Info

Measurement of total and free testosterone is key in diagnosis of androgen excess or deficiency. Free testosterone is best measured by equilibrium dialysis, while total testosterone is measured by HPLC with tandem mass spectrometry.1-3 Free testosterone is estimated in this profile using these recommended techniques.
Tritiated testosterone is added to the sample and allowed to dialyze across a membrane. Once equilibrium has been achieved, the solutions on both sides of the membrane are sampled to determine the percent free testosterone. Total testosterone is measured by HPLC with tandem mass spectrometry. Serum free testosterone is then calculated by multiplying the percent free testosterone by the total testosterone concentration with unit correction.
Limitations
This method is recommended for testing women, children, and hypogonadal men.

Specimen Type

Container

Gold Top Tube

Collection Instructions

Container/Tube: Gold Top Tube
Specimen: 2 mL serum ( 1 mL min)
Transport Temperature Refrigerated
Collection
Serum must be separated from cells within 45 minutes of venipuncture.

Transport Instructions

Specimen Stability

6 Days Room Temperature
7 Days Refrigerated
2.6 Years Frozen

Methodology

Testosterone: high-pressure liquid chromatography (HPLC)/tandem mass spectrometry; free testosterone: equilibrium dialysis

Days Performed

TAT: 6 - 10 Days

Performing Laboratory

LabCorp- Endocrine Sciences

CPT

84402
84403
LOINC Code: 2991-8

PDM

225709

Results