Testosterone, Free, Direct With Total Testosterone
Also known as: Free Testosterone, Direct and Total
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). See individual test descriptions for more information.
Special Instructions
It is important to state the patient’s age and sex on the test request form. The panel includes Testosterone, Total, which may exhibit interference if the sample is collected from an individual consuming high doses of biotin. Patients should cease biotin consumption at least 72 hours before sample collection.
Limitations
A pediatric reference interval has not been established for the direct free testosterone test. Interference may occur in samples with gross lipemia, gross hemolysis, or gross icterus, potentially causing erroneous results, especially for free testosterone. Plasma specimens are also rejected for the free testosterone component.
Methodology
Immunoassay
Biomarkers
LOINC Codes
- 58952-3
- 2986-8
- 2991-8
Result Turnaround Time
4-7 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
1 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.
Storage Instructions
Room temperature
Causes for Rejection
Gross lipemia (may yield erroneously high free testosterone results); plasma specimen; gross hemolysis and/or gross icterus cause for rejection of direct free testosterone
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
Other tests from different labs that may be relevant