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Testosterone, Free (Serum/Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of free (unbound) testosterone in your blood, which is the active form of this hormone that can easily enter cells to influence growth, development, and reproductive functions.

Quick summary

["Free testosterone helps balance hormone levels and supports overall health, especially in men and women."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
72410-4
Short code
Testost pre HCG SerPl-sCnc
Synonyms
Testost pre HCG SerPl-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
5
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84702
SNOMED
275917004
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order a free testosterone test to evaluate hormonal health, diagnose conditions like low testosterone (hypogonadism) or high testosterone (hyperandrogenism), assess fertility issues, or check for symptoms of hormone-related disorders. It can also help monitor treatment responses for hormone-related conditions.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the blood draw if your test is part of a broader metabolic or hormonal panel. Avoid smoking or consuming alcohol for 24 hours before testing.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick. The blood sample is then sent to a lab for analysis using an immunoassay method to measure free testosterone levels.

What Are the Results?

Results are typically reported as a concentration value (in picograms per milliliter, pg/mL, or similar units) compared to reference ranges, which can vary slightly by lab. Your results will be interpreted by your healthcare provider in the context of your overall health and symptoms.

Reference range

Non-pregnant: <5 mIU/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free Testosterone

Frequently asked questions

What Does This Test Tell Us?
Free testosterone levels can indicate whether your body is producing adequate hormone levels for normal function. Low levels may suggest conditions like pituitary disorders, ovarian/testicular dysfunction, or aging-related changes. High levels could point to conditions like polycystic ovary syndrome (PCOS) or Cushing’s syndrome, among others. Always discuss results with your provider.
What Are Common Reasons for Testing?
Common reasons include evaluating symptoms of low or high testosterone (e.g., fatigue, low libido, irregular periods, or acne), diagnosing fertility issues, assessing hormonal imbalances, or monitoring treatment for hormone-related disorders.
How Often Should This Test Be Done?
Frequency depends on your health status and medical needs. Your provider will determine how often to repeat the test, such as annually for monitoring or more frequently if symptoms or conditions change.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy