Testosterone, Free and Total, Includes Sex Hormone-Binding Globulin (Adult Males or Individuals on Testosterone Hormone Therapy)

Also known as: FREE T

Clinical Use

Use

This test provides a calculated value for free testosterone concentration using total testosterone measured by immunoassay. It is used to evaluate hypogonadism in cisgender males with a total testosterone concentration at the lower limit of normal and may be used to evaluate testosterone status in individuals with protein-binding abnormalities or to monitor testosterone hormone therapies. It is not recommended for instances where low testosterone concentrations are expected, such as in children and cisgender females; in these cases, testing by mass spectrometry is recommended.

Special Instructions

Not provided.

Limitations

Testosterone immunoassays are both imprecise and inaccurate at low testosterone concentrations, such as those found in children and cisgender females. For these individuals, testing by mass spectrometry is recommended to ensure accurate results. The concentration of free testosterone is calculated based on the binding constant of testosterone to sex hormone-binding globulin, and the reference intervals are not established for males younger than 14 years or cisgender females.

Test Details

New York Approved

Methodology

Immunoassay (ECLIA)

Biomarkers

2 components

Testosterone by Immunoassay • ECLIASex Hormone Binding Globulin • ECLIA

LOINC Codes

Order Codes

13967-5 - SHBG SerPl-sCnc
15432-8 - Testost Free MFr SerPl
2986-8 - Testost SerPl-mCnc
2991-8 - Testost Free SerPl-mCnc

Result Codes

2991-8 - Testost Free SerPl-mCnc
15432-8 - Testost Free MFr SerPl
2986-8 - Testost SerPl-mCnc
13967-5 - SHBG SerPl-sCnc

Result Turnaround Time

1 day

Specimen

Serum

Volume

1 mL

Minimum Volume

0.6 mL

Container

Serum separator tube or green (lithium heparin)

Collection Instructions

Allow serum to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer to an ARUP Standard Transport Tube.