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Turnaround Time
4 - 7 days
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
State patient's age and sex on the test request form.
This panel includes Testosterone, Total, which may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.
Limitations
A pediatric reference interval has not been established for the direct free testosterone test.
Methodology
Free: Direct analog enzyme immunoassay (EIA); Total: electrochemiluminescence immunoassay (ECLIA)
Related Documents
For more information, please view the literature below.
Frequently Asked Questions: Testosterone by Mass Spectrometry—New Profiles
Specimen Requirements
Information on collection, storage, and volume
Specimen
Serum
Volume
2 mL
Minimum Volume
1 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier 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
Collection
If a red-top tube is used, transfer separated serum to a plastic transport tube.