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HelpOrder Code LABTSTBF Testosterone, Total, Bioavailable, and Free, Serum
Additional Codes
| Mayo Test ID |
|---|
| TTFB |
| EPIC Test ID |
|---|
| LABTSTBF |
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)
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
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
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 a plastic vial
Specimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days |
| Frozen | 60 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | Reject |
| Gross icterus | OK |
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
*Forest MG, Cathiard AM, Bertrand JA. Total and unbound testosterone levels in the newborn and in normal and hypogonadal children: use of a sensitive radioimmunoassay for testosterone. 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
*Forest MG, Cathiard AM, Bertrand JA. Total and unbound testosterone levels in the newborn and in normal and hypogonadal children: use of a sensitive radioimmunoassay for testosterone. 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
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Day(s) Performed
Monday through Saturday
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)
CPT Code Information
84402
84403
84410
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 |
Method Description
Total Testosterone:
Deuterated stable isotope (d3-testosterone) is added to a serum sample as internal standard. Protein is precipitated from the mixture. The testosterone and internal standard are extracted from the resulting supernatant by an on-line 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. Epitestosterone does not interfere with this liquid chromatography tandem mass spectrometry (LC-MS/MS) method for total testosterone.(Unpublished Mayo method)
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 that is immersed in dialysis buffer. The sample is dialyzed. During buffered dialysis, any testosterone that is unbound to sex hormone-binding globulin (SHBG) or albumin is free to pass through the semi-permeable dialysis membrane, while testosterone molecules bound to the binding proteins will be held inside the membrane. After dialysis, the buffered dialysate is analyzed for free testosterone by LC-MS/MS with stable isotope (testosterone-[13]C3) after derivatization.(Unpublished Mayo method)
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 LC-MS/MS. Bioavailable testosterone shows a strong correlation to free testosterone by equilibrium dialysis and may be considered a suitable alternative.(Unpublished Mayo method)