Testosterone, Free (Adult Males or Individuals on Testosterone Hormone Therapy)
Provides a calculated value for free testosterone concentration using total testosterone measured by immunoassay. Use to evaluate hypogonadism in cisgender males with a total testosterone concentration at the lower limit of normal. May be used to evaluate testosterone status in individuals with protein-binding abnormalities or to monitor testosterone hormone therapies. Not recommended when low testosterone concentrations, such as those found in children and cisgender females, are expected. For these individuals, testing by mass spectrometry is recommended; refer to Testosterone, Free (Adult Females, Children, or Individuals on Testosterone-Suppressing Hormone Therapy) (0081059).
To compare this test to other testosterone tests, refer to the ARUP Testosterone Tests Comparison table.
New York DOH Approval Status
Collect specimen between 6-10 a.m.
Serum separator tube or green (lithium heparin).
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.4 mL)
After separation from cells: Ambient: 48 hours; Refrigerated: 1 week; Frozen: 2 months
Quantitative Electrochemiluminescent Immunoassay/Calculation
Within 24 hours
14-15 years: 3-138 pg/mL
16-17 years: 38-173 pg/mL
18 years and older: 47-244 pg/mL
Tanner Stage IV: 35-169 pg/mL
Tanner Stage V: 41-239 pg/mL
Free testosterone concentration is calculated using total testosterone (measured by immunoassay) and the binding constant of testosterone and sex hormone-binding globulin (SHBG). 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; refer to Testosterone, Free (Adult Females, Children, or Individuals on Testosterone-Suppressing Hormone Therapy) (ARUP test code 0081059).
For individuals on testosterone hormone therapy, refer to cisgender male reference intervals. No reference intervals have been established for males younger than 14 years or for cisgender females. For a complete set of all established reference intervals, refer to ltd.aruplab.com/Tests/Pub/0070111.
|Component Test Code*||Component Chart Name||LOINC|
|0070113||Testosterone, Free Calculation||2991-8|
- Free testosterone
- serum testosterone free