Test Code TESTF Testosterone, Total, Bioavailable, and Free, Serum
Reporting Name
Testosterone, Total, Bio, Free, SUseful For
Second- or third-order test for evaluating testosterone status (eg, when abnormalities of sex hormone-binding globulin are present)
Performing Laboratory

Specimen Type
Serum RedOrdering Guidance
The preferred test for diagnosis of mild abnormalities of testosterone homeostasis, particularly if abnormalities in sex hormone-binding globulin function or levels are present, is TTBS / Testosterone, Total and Bioavailable, Serum.
Necessary Information
Patient's age and sex are required.
Specimen Required
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 3.5 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial
Specimen Minimum Volume
2 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum Red | Refrigerated (preferred) | 14 days | |
Frozen | 60 days |
Reference Values
TESTOSTERONE, TOTAL
Males
0-5 months: 75-400 ng/dL
6 months-9 years: <7-20 ng/dL
10-11 years: <7-130 ng/dL
12-13 years: <7-800 ng/dL
14 years: <7-1,200 ng/dL
15-16 years: 100-1,200 ng/dL
17-18 years: 300-1,200 ng/dL
≥19 years: 240-950 ng/Dl
Tanner Stages*
I (prepubertal): <7-20
II: 8-66
III: 26-800
IV: 85-1,200
V (young adult): 300-950
Females
0-5 months: 20-80 ng/dL
6 months-9 years: <7-20 ng/dL
10-11 years: <7-44 ng/dL
12-16 years: <7-75 ng/dL
17-18 years: 20-75 ng/dL
≥19 years: 8-60 ng/dL
Tanner Stages*
I (prepubertal): <7-20
II: <7-47
III: 17-75
IV: 20-75
V (young adult): 12-60
*Puberty onset (transition from Tanner stage I to Tanner stage II) occurs for boys at a median age of 11.5 (±2) years and for girls at a median age of 10.5 (±2) years. There is evidence that it may occur up to 1 year earlier in obese girls and in African American girls. For boys, there is no definite proven relationship between puberty onset and body weight or ethnic origin. Progression through Tanner stages is variable. Tanner stage V (young adult) should be reached by age 18.
TESTOSTERONE, FREE
Males (adult):
20-<25 years: 5.25-20.7 ng/dL
25-<30 years: 5.05-19.8 ng/dL
30-<35 years: 4.85-19.0 ng/dL
35-<40 years: 4.65-18.1 ng/dL
40-<45 years: 4.46-17.1 ng/dL
45-<50 years: 4.26-16.4 ng/dL
50-<55 years: 4.06-15.6 ng/dL
55-<60 years: 3.87-14.7 ng/dL
60-<65 years: 3.67-13.9 ng/dL
65-<70 years: 3.47-13.0 ng/dL
70-<75 years: 3.28-12.2 ng/dL
75-<80 years: 3.08-11.3 ng/dL
80-<85 years: 2.88-10.5 ng/dL
85-<90 years: 2.69-9.61 ng/dL
90-<95 years: 2.49-8.76 ng/dL
95-100+ years: 2.29-7.91 ng/dL
Males (children):
<1 year: Term infants
1-15 days: 0.20-3.10 ng/dL*
16 days-1 year: Values decrease gradually from newborn (0.20-3.10 ng/dL) to prepubertal levels
*J Clin Endocrinol Metab 1973;36(6):1132-1142
1-8 years: <0.13 ng/dL
9 years: <0.13-0.45 ng/dL
10 years: <0.13-1.26 ng/dL
11 years: <0.13-5.52 ng/dL
12 years: <0.13-9.28 ng/dL
13 years: <0.13-12.6 ng/dL
14 years: 0.48-15.3 ng/dL
15 years: 1.62-17.7 ng/dL
16 years: 2.93-19.5 ng/dL
17 years: 4.28-20.9 ng/dL
18 years: 5.40-21.8 ng/dL
19 years: 5.36-21.2 ng/dL
Females (adult):
20-<25 years: <0.13-1.08 ng/dL
25-<30 years: <0.13-1.06 ng/dL
30-<35 years: <0.13-1.03 ng/dL
35-<40 years: <0.13-1.00 ng/dL
40-<45 years: <0.13-0.98 ng/dL
45-<50 years: <0.13-0.95 ng/dL
50-<55 years: <0.13-0.92 ng/dL
55-<60 years: <0.13-0.90 ng/dL
60-<65 years: <0.13-0.87 ng/dL
65-<70 years: <0.13-0.84 ng/dL
70-<75 years: <0.13-0.82 ng/dL
75-<80 years: <0.13-0.79 ng/dL
80-<85 years: <0.13-0.76 ng/dL
85-<90 years: <0.13-0.73 ng/dL
90-<95 years: <0.13-0.71 ng/dL
95-100+ years: <0.13-0.68 ng/dL
Females (children):
<1 year: Term infants
1-15 days: <0.13-0.25 ng/dL*
16 days-1 year: Values decrease gradually from newborn (<0.13-0.25 ng/dL) to prepubertal levels
*J Clin Endocrinol Metab 1973;36(6):1132-1142
1-4 years: <0.13 ng/dL
5 years: <0.13 ng/dL
6 years: <0.14 ng/dL
7 years: <0.13-0.23 ng/dL
8 years: <0.13-0.34 ng/dL
9 years: <0.13-0.46 ng/dL
10 years: <0.13-0.59 ng/dL
11 years: <0.13-0.72 ng/dL
12 years: <0.13-0.84 ng/dL
13 years: <0.13-0.96 ng/dL
14 years: <0.13-1.06 ng/dL
15-18 years: <0.13-1.09 ng/dL
19 years: <0.13-1.08 ng/dL
TESTOSTERONE, BIOAVAILABLE
Males
≤19 years: Not established
20-29 years: 83-257 ng/dL
30-39 years: 72-235 ng/dL
40-49 years: 61-213 ng/dL
50-59 years: 50-190 ng/dL
60-69 years: 40-168 ng/dL
≥70 years: Not established
Females (non-oophorectomized)
≤19 years: Not established
20-50 years (on oral estrogen): 0.80-4.0 ng/dL
20-50 years (not on oral estrogen): 0.80-10 ng/dL
>50 Years: Not established
Day(s) Performed
Monday through Saturday
Test Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84402
84403
84410
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
TTFB | Testosterone, Total, Bio, Free, S | 58716-2 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
82978 | Testosterone, Bioavailable, S | 2990-0 |
3631 | Testosterone Free | 2991-8 |
8533 | Testosterone, Total, S | 2986-8 |
Clinical Reference
1. Manni A, Pardridge WM, Cefalu W, et al: Bioavailability of albumin-bound testosterone. J Clin Endocrinol Metab. 1985 Oct;61(4):705- 710. doi: 10.1210/jcem-61-4-705.
2. New MI, Josso N: Disorders of gonadal differentiation and congenital adrenal hyperplasia. Endocrinol Metab Clin North Am. 1988;17(2):339-366
3. Dumesic DA: Hyperandrogenic anovulation: a new view of polycystic ovary syndrome. Postgrad Obstet Gynecol. 1995 June;15(13)
4. Morley JE, Perry HM 3rd: Androgen deficiency in aging men: role of testosterone replacement therapy. J Lab Clin Med. 2000 May;135:370-378. doi: 10.1067/mlc.2000.106455
5. Goldman AL, Bhasin S, Wu FCW, et al: A reappraisal of testosterone's binding in circulation: physiological and clinical implications. Endocr Rev. 2017;38(4):302-324. doi: 10.1210/er.2017-00025
Method Description
Total Testosterone:
Deuterated stable isotope (d3-testosterone) is added to a 0.2-mL serum sample as an internal standard. Protein is precipitated from the mixture by the addition of acetonitrile. The testosterone and internal standard are extracted from the resulting supernatant by an online extraction utilizing high-throughput liquid chromatography. This is followed by conventional liquid chromatography and analysis on a tandem mass spectrometer equipped with a heated nebulizer ion source.(Wang C, Catlin DH, Demers LM, et al: Measurement of total testosterone in adult men: comparison of current laboratory methods versus liquid chromatography-tandem mass spectrometry. J Clin Endocrinol Metab. 2004 Feb;89(2):534-543; Taieb J, Mathian B, Millot F, et al: Testosterone measured by 10 immunoassays and by isotope-dilution gas chromatography-mass spectrometry in sera from 116 men, women, and children. Clin Chem. 2003 Aug;49:1381-1395)
Free Testosterone:
This method utilizes equilibrium dialysis to analyze and determine the host serum's binding capacity for testosterone. Patient sample is placed inside a dialysis well which is immersed in dialysis buffer. The sample is dialyzed. During buffered dialysis, any testosterone which is unbound to sex hormone binding globulin (SHBG) or albumin is free to pass through the semi-permeable dialysis membrane while those testosterone molecules bound to the binding proteins will be held inside the membrane. After dialysis, the buffered dialysate is analyzed for free testosterone by liquid chromatography-tandem mass spectrometry.(Bhasin S, Ozimek N: Optimizing diagnostic accuracy and treatment decisions in men with testosterone deficiency. Endocr Pract. 2021 Dec;27(12):1252-1259. doi: 10.1016/j.eprac.2021.08.002)
Bioavailable Testosterone:
The method is based on the differential precipitation of SHBG. SHBG bound testosterone is precipitated in patient sample, leaving the bioavailable testosterone in the supernatant. After addition of (13)C-labeled testosterone internal standard (IS), the bioavailable testosterone and IS are extracted from the supernatant. The bioavailable testosterone and IS are then derivatized and analyzed by liquid chromatography tandem mass spectrometry. Bioavailable testosterone shows a strong correlation to free testosterone by equilibrium dialysis and may be considered a suitable alternative.(Unpublished Mayo Method)
Report Available
3 to 5 daysReject Due To
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
Method Name
FRTST: Equilibrium Dialysis / Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
TTST: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
BATS: Differential Precipitation/Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Profile Information
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
TTST | Testosterone, Total, S | Yes | Yes |
FRTST | Testosterone, Free, S | No | Yes |
BATS | Testosterone, Bioavailable, S | No | Yes |