Testosterone, Free, Direct
Also known as: Free Testosterone, Direct
Use
Evaluate hirsutism and masculinization in women; evaluate testicular function in clinical states where the testosterone binding proteins may be altered (obesity, cirrhosis, thyroid disorders)
Special Instructions
It is important to state the patient's age and sex on the test request form to ensure accurate interpretation of the test results.
Limitations
A pediatric reference interval has not been established for this analyte. Gross lipemia can yield erroneously high free testosterone results. Additionally, the routine total testosterone assays are typically not sensitive enough to accurately quantify the free testosterone fraction directly. Therefore, free testosterone is estimated using a direct, analogue immunoassay method, which may produce varied results compared to equilibrium dialysis methods.
Methodology
Immunoassay (Other)
Biomarkers
LOINC Codes
- 2991-8
- 2991-8
Result Turnaround Time
4-6 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.3 mL
Container
Red-top tube or gel-barrier tube
Collection Instructions
If a red-top tube is used, transfer separated serum to a plastic transport tube.
Causes for Rejection
Gross lipemia; gross hemolysis; gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
Other tests from different labs that may be relevant