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Test Code TESTT Testosterone, Total and Free, Serum

Reporting Name

Testosterone, Total and Free, S

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 females

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum Red

Advisory Information

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

Container/Tube: Red top (serum gel/SST are not acceptable)

Specimen Volume: 2.5 mL

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 14 days
  Frozen  60 days

Special Instructions

Reference Values


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

*Citation: J Clin Endocrinol Metab 1973;36(6):1132-1142


1-8 years: <0.04-0.11 ng/dL

9 years: <0.04-0.45 ng/dL

10 years: <0.04-1.26 ng/dL

11 years: <0.04-5.52 ng/dL

12 years: <0.04-9.28 ng/dL

13 years: <0.04-12.6 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: 0.06-1.08 ng/dL

25-<30 years: 0.06-1.06 ng/dL

30-<35 years: 0.06-1.03 ng/dL

35-<40 years: 0.06-1.00 ng/dL

40-<45 years: 0.06-0.98 ng/dL

45-<50 years: 0.06-0.95 ng/dL

50-<55 years: 0.06-0.92 ng/dL

55-<60 years: 0.06-0.90 ng/dL

60-<65 years: 0.06-0.87 ng/dL

65-<70 years: 0.06-0.84 ng/dL

70-<75 years: 0.06-0.82 ng/dL

75-<80 years: 0.06-0.79 ng/dL

80-<85 years: 0.06-0.76 ng/dL

85-<90 years: 0.06-0.73 ng/dL

90-<95 years: 0.06-0.71 ng/dL

95-100+ years: 0.06-0.68 ng/dL


Females (children):

<1 year: Term infants


1-15 days: 0.06-0.25 ng/dL*

16 days-1 year: Values decrease gradually from newborn (0.06-0.25 ng/dL) to prepubertal levels

*Citation: J Clin Endocrinol Metab, 36(6):1132-1142, 1973


1-4 years: <0.04 ng/dL

5 years: <0.04-0.07 ng/dL

6 years: <0.04-0.14 ng/dL

7 years: <0.04-0.23 ng/dL

8 years: <0.04-0.34 ng/dL

9 years: <0.04-0.46 ng/dL

10 years: <0.04-0.59 ng/dL

11 years: <0.04-0.72 ng/dL

12 years: <0.04-0.84 ng/dL

13 years: <0.04-0.96 ng/dL

14 years: <0.04-1.06 ng/dL

15-18 years: <0.04-1.09 ng/dL

19 years: 0.06-1.08 ng/dL




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



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

Day(s) and Time(s) Performed

Monday through Friday; 2 p.m.

Saturday, Sunday; Varies

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 U.S. Food and Drug Administration.

CPT Code Information




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, S 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):705-10

2. New MI, Josso N: Disorders of gonadal differentiation and congenital adrenal hyperplasia. Endocrinol Metab Clin North Am. 1988 Jun;17(2):339-366

3. Morley JE, Perry HM III: Androgen deficiency in aging men: Role of testosterone replacement therapy. J Lab Clin Med. 2000 May;135(5):370-378

4. Sizonenko PC, Paunier L: Hormonal changes in puberty III: Correlation of plasma dehydroepiandrosterone, testosterone, FSH and LH with stages of puberty and bone age in normal boys and girls and in patients with Addison's disease or hypogonadism or with premature or late adrenarche. J Clin Endocrinol Metab. 1975 Nov;41(5):894-904

5. Goudas VT, Dumesic DA: Polycystic ovary syndrome. Endocrinol Metab Clin North Am. 1997 Dec;26(4):893-912

6. Braunstein GD: Androgen insufficiency in women: Summary of critical issues. Fertil Steril. 2002 Apr;77 Suppl 4:S94-99

7. Juul A, Skakkebaek NE: Androgens and the aging male. Hum Reprod Update. 2002 Sep-Oct;8(5):423-433

8. Hackbarth JS, Hoyne JB, Grebe SK, Singh RJ: Accuracy of calculated free testosterone differs between equations and depends on gender and SHBG concentration. Steroids. 2011 Jan;76(1-2):48-55

9. Goldman AL, Bhasin S, Wu FCW, et al: A reappraisal of testosterone’s binding in circulation: Physiological and clinical implications. Endocr Rev. 2017 Aug;38(4):302-324

Method Description

Free Testosterone:

This method is based on equilibrium dialysis in which free-labeled testosterone is allowed to pass through a semipermeable membrane, whereas testosterone bound to the sex hormone-binding globulin (SHBG) remains inside the dialysis tubing. After dialysis, radioactivity is measured both inside and outside the tubing; the free testosterone results are expressed as a percentage of total testosterone. The resulting percentage is multiplied by the total testosterone concentration obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and an absolute free testosterone value is obtained.(Vermeulen A, Stoica T, Verdonck L: The apparent free testosterone concentration, an index of androgenicity. J Clin Endocrinol Metab. 1971;33:759-767; Bammann BL, Coulam C, Jiang NS: Total and free testosterone during pregnancy. Am J Obstet Gynecol. 1980;137:293-298)


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 (HTLC). 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;89:534-543; 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;49:1381-1395)

Analytic Time

3 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Method Name

FRTST: Equilibrium Dialysis

TTST: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)


If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.

Profile Information

Test ID Reporting Name Available Separately Always Performed
FRTST Testosterone, Free, S No Yes
TTST Testosterone, Total, S Yes Yes

Secondary ID