Testosterone, Free (Adult Males or Individuals on Testosterone Hormone Therapy)
Also known as: FREE T2
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. The test may also be used to evaluate testosterone status in individuals with protein-binding abnormalities or to monitor testosterone hormone therapies. However, it is not recommended for individuals where low testosterone concentrations are expected, such as children and cisgender females, for whom testing by mass spectrometry is advised.
Special Instructions
Collect specimen between 6-10 a.m. It is essential to allow serum specimen to clot completely at room temperature and to separate serum or plasma from cells as soon as possible or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube, with a minimum of 0.6 mL required.
Limitations
Testosterone immunoassays are 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. No reference intervals have been established for males younger than 14 years or for cisgender females. Additionally, testing is not recommended for conditions where low testosterone concentrations are expected.
New York Approved
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 2991-8
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.6 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Collect serum separator tube or green (lithium heparin) tube. Allow serum specimen to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection.
Patient Preparation
Collect specimen between 6-10 a.m.
Storage Instructions
Refrigerated.
Causes for Rejection
EDTA plasma.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 1 week |
| Frozen | 2 months |