Ordering Recommendation

Provides a calculated value for free testosterone concentration using total testosterone measured by mass spectrometry. May be used to evaluate hyperandrogenism in children and cisgender females, monitor testosterone-suppressing hormone therapies (eg, antiandrogens or estrogens), evaluate testosterone status in individuals with protein-binding abnormalities, or evaluate hypogonadism in cisgender males.

To compare this test to other testosterone tests, refer to the ARUP Testosterone Tests Comparison table.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Collect between 6-10 a.m.


Serum separator tube or green (sodium or lithium heparin).

Specimen Preparation

Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP standard transport tube. (Min: 0.8 mL)

Storage/Transport Temperature


Unacceptable Conditions

EDTA plasma.


After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 6 months


Quantitative High Performance Liquid Chromatography-Tandem Mass Spectrometry/Electrochemiluminescent Immunoassay/Calculation




1-5 days

Reference Interval

Test Number
Reference Interval
  Testosterone, Free by Mass Spec
Male (pg/mL)
Female (pg/mL)
1-6 years Less than 0.6 Less than 0.6
7-9 years 0.1-0.9 0.6-1.8
10-11 0.1-6.3 0.1-3.5
12-13 0.5-98.0 0.9-6.8
14-15 3-138.0 1.2-7.5
16-17 38.0-173.0 1.2-9.9
18 years and older 47-244 Not Applicable
18-30 Not Applicable 0.8-7.4
31-40 Not Applicable 1.3-9.2
41-51 Not Applicable 1.1-5.8
Postmenopausal Not Applicable 0.6-3.8
Tanner Stage I Less than or equal to 3.7 Less than 2.2
Tanner Stage II 0.3-21 0.4-4.5
Tanner Stage III 1.0-98.0 1.3-7.5
Tanner Stage IV 35.0-169.0 1.1-15.5
Tanner Stage V 41.0-239.0 0.8-9.2

Interpretive Data

Free testosterone concentration is calculated using total testosterone (measured by mass spectrometry) and the binding constant of testosterone and sex hormone-binding globulin (SHBG).

For individuals on testosterone-suppressing hormone therapies (e.g., antiandrogens or estrogens), refer to cisgender female reference intervals. For a complete set of all established reference intervals, refer to ltd.aruplab.com/Tests/Pub/0081059.

Compliance Category

Laboratory Developed Test (LDT)


Total testosterone and SHBG are measured and free testosterone is estimated from these measurements.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0081096 Testosterone, Free by Mass Spec 49042-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


Testosterone, Free (Adult Females, Children, or Individuals on Testosterone-Suppressing Hormone Therapy)