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Testosterone, Total and Free Androgen Index

Testosterone, Total and Free Androgen Index (Calculated)

Test ID: A857

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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. Total testosterone includes testosterone bound to protein and biologically active free testosterone. Abnormal testosterone levels can influence sex drive, energy, mental health, muscle mass, body weight, fertility, and bone health.



How to order a test

What is Included?

Measurement of total testosterone and SHBG by chemiluminescent microparticle immunoassays. Calculation of the Free Androgen Index (FAI) by:

FAI = Total Testosterone (nmol/L) x 100 / SHBG (nmol/L)

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


Preparation Before Specimen Collection

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

Specimen Type



50 μL in a microtainer


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



To measure total testosterone and SHBG levels in a blood sample and to calculate the FAI. This aids in the investigation of androgen activity.


  • 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. 


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

SHBG: Chemiluminescent microparticle immunoassay (Alinity i SHBG assay)

Free Androgen Index (FAI) is calculated by:

FAI = Total Testosterone (nmol/L) x 100 / SHBG (nmol/L)

This ratio correlates well with calculated values of free testosterone and helps to discriminate subjects with excessive androgen activity from normal individuals.

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.  

Free Androgen Index in Males:
21 – 49 years: 24.5 – 113.3 %
≥ 50 years: 19.3 – 118.4 %

Free Androgen Index in Females:
21 – 49 years: 0.7 – 8.7 %
≥ 50 years: 0.5 – 4.7 %

These reference ranges were obtained from the Alinity i 2nd Generation Testosterone package insert.