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HelpTest Code FTG Testosterone, Total and Free, Serum
Reporting Name
Testosterone, Total and Free, SSCH Clinical System Name: Testosterone, Free + Total
Useful For
Alternative, second-level test for suspected increases or decreases in physiologically active testosterone:
-Assessment of androgen status in cases with suspected or known sex hormone-binding globulin-binding abnormalities
-Assessment of functional circulating testosterone in early pubertal boys and older men
-Assessment of functional circulating testosterone in women with symptoms or signs of hyperandrogenism but normal total testosterone levels
-Monitoring of testosterone therapy or antiandrogen therapy in older men and in female patients
Ordering Guidance
This is a second-level test for suspected increases or decreases in physiologically active testosterone. The preferred test for assessment of active testosterone 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: 2.5 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial
Collect 5.0 mL whole blood in Red Top.
Specimen Type
Serum RedSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days | |
| Frozen | 60 days |
Day(s) Performed
Monday through Saturday
TAT: 5 - 7 days
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Method Name
FRTST: Equilibrium Dialysis/Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
TTST: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Method Description
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 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)
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)
Reference Values
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, 36(6):1132-1142, 1973
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, 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
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
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TGRP | Testosterone, Total and Free, S | 58952-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 3631 | Testosterone Free | 2991-8 |
| 8533 | Testosterone, Total, S | 2986-8 |
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| FRTST | Testosterone, Free, S | No | Yes |
| TTST | Testosterone, Total, S | Yes | Yes |
Report Available
3 to 7 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Forms
If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.