Testosterone, Total and Free (Calculated)

Introduction

Testosterone is the primary sex hormone in males, but it is also important in females. Testosterone is secreted from the testicles in males, and from the ovaries in females. Free testosterone is the biologically active form of the hormone. Abnormal free testosterone levels can influence muscle mass, sleep, energy, fertility, skin health, and sex drive.

Pricing

$179

How to order a test

Synonyms

• Free Testosterone by Vermeulen Equation
• Free Testosterone, Calculated

What is Included?

Measurement of free testosterone levels using the Vermeulen equation based on laboratory measurements of total testosterone, SHBG, and albumin.

Turnaround Time

1 – 3 business days
The turnaround time is not guaranteed. The average turnaround time is 1 – 3 business days from the date that the sample arrives at the laboratory. Shipping time for the sample is not included. Additional time is required if the case requires confirmatory or reflex testing, or if the sample is insufficient, or if a recollection is required.

Related Documents

Additional Information and Resources

» The wide influence of testosterone on male health
» Is there such a thing as ‘male menopause’?
» What are the signs of low testosterone in males?
» Possible causes of erectile dysfunction and how to treat them ​

Preparation Before Specimen Collection

Collect blood sample in the morning, as testosterone levels can fluctuate throughout the day

Specimen Type

Blood

Volume

50 μL in a microtainer

Container

Microtainer (regular blood tube)

Collection Method

This test requires a blood sample from a finger prick. All supplies for sample collection are provided in the kit.

1. First wash and dry hands. Warm hands aid in blood collection.
2. Clean the finger prick site with the alcohol swab and allow to air dry.
3. Use the provided lancet to puncture the skin in one quick, continuous and deliberate stroke.
4. Wipe away the first drop of blood.
5. Massage hand and finger to increase blood flow to the puncture site. Angle arm and hand downwards to facilitate blood collection on the fingertip.
6. Drip blood into the microtainer tube.
7. Dispose of all sharps safely and return sample to the laboratory in the provided prepaid return shipping envelope.

NOTES: Avoid squeezing or ‘milking’ the finger excessively. If more blood is required and blood flow stops, perform a second skin puncture on another finger. Do not touch the fingertip.

Specimen Storage

Maintain specimen at temperatures between 2°C and 30°C during storage and transport.

Specimen Stability

Blood samples can be refrigerated or kept at room temperature for up to 7 days.

Causes for Rejection

• Incorrect or incomplete patient identification
• Incorrect specimen collection
• Inappropriate storage and transport conditions
• Incorrect specimen volume

Purpose

To measure free testosterone levels in a blood sample to aid in the investigation of fertility and androgen activity in men and women.

Limitations

• This report is not intended for use in medico-legal applications.
• These results should be interpreted in conjunction with other laboratory and clinical information.
• Correct specimen collection and handling is required for optimal assay performance.
• Assay interference may occur in specimens from individuals routinely exposed to animals or to animal serum products. Additional clinical or diagnostic information may be required for these specimens.
• False results may occur in specimens from individuals that have received preparations of mouse monoclonal antibodies for diagnosis or therapy. Additional clinical or diagnostic information may be required for these specimens.
• This assay cannot be used for specimens from patients receiving Nandrolone treatment. 

Methodology

Total Testosterone: Chemiluminescent microparticle immunoassay (Alinity i 2^nd Generation Testosterone assay)

SHBG: Chemiluminescent microparticle immunoassay (Alinity i SHBG assay)

Albumin: Colorimetric (Bromcresol Purple) (Alinity c Albumin BCP assay)

Free testosterone levels are calculated using the Vermeulen equation.

Reference Intervals

Total Testosterone in Males¹:
18 – 39 years: 229 – 902 ng/dL (7.94 – 31.28 nmol/L)
40 – 49 years: 208 – 902 ng/dL (7.21 – 31.28 nmol/L)
50 – 59 years: 192 – 902 ng/dL (6.66 – 31.28 nmol/L)
60 – 79 years: 190 – 902 ng/dL (6.59 – 31.28 nmol/L)
80 – 99 years: 119 – 902 ng/dL (4.13 – 31.28 nmol/L)

Total Testosterone in Females:
14 – 18 years²: 18 – 57 ng/dL (0.62 – 1.98 nmol/L)
≥ 19 years³: 8 – 60 ng/dL (0.28 – 2.08 nmol/L)

These reference ranges were obtained from:
¹ Travison TG, et al. Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the United States and Europe. J Clin Endocrinol Metab. 2017 Apr 1;102(4):1161-1173.
² Raizman JE, et al. Pediatric reference intervals for calculated free testosterone, bioavailable testosterone and free androgen index in the CALIPER cohort. Clin Chem Lab Med. 2015 Sep 1;53(10):e239-43.
³ Endocrine Society

SHBG in Adult Males: 11.2 – 78.1 nmol/L
SHBG in Adult Females: 11.7 – 137.2 nmol/L

These reference ranges were obtained from the Alinity i SHBG package insert.  

Albumin:
16 – 29 years, Males: 4.6 – 5.3 g/dL
16 – 54 years, Females: 3.9 – 5.0 g/dL
30 – 54 years, Males: 4.4 – 5.1 g/dL
55 – 79 years: 4.2 – 5.0 g/dL

These reference ranges were obtained from Rifai N, Horvath AR, & Wittwer C. (2018). Tietz textbook of clinical chemistry and molecular diagnostics (Sixth edition.). St. Louis, Missouri: Elsevier.

Free Testosterone in Males¹:
18 – 39 years: 20 – 293 pg/mL (69 – 1017 pmol/L)
40 – 49 years: 18 – 293 pg/mL (63 – 1017 pmol/L)
50 – 79 years: 15 – 259 pg/mL (52 – 899 pmol/L)
≥ 80 years: 9 – 259 pg/mL (31 – 899 pmol/L)

Free Testosterone in Females²:
≥ 18 years: 1 – 8.5 pg/mL (3.5 – 29.5 pmol/L)

These reference ranges were obtained from:
¹ Travison TG, et al. Harmonized Reference Ranges for Circulating Testosterone Levels in Men of Four Cohort Studies in the United States and Europe. J Clin Endocrinol Metab. 2017 Apr 1;102(4):1161-1173.
² Rifai N, Horvath AR, & Wittwer C. (2018). Tietz textbook of clinical chemistry and molecular diagnostics (Sixth edition.). St. Louis, Missouri: Elsevier.