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Serum/plasma free testosterone concentration

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

This test measures the amount of free (unbound) testosterone in your blood, which is an important form of the male hormone responsible for muscle development, bone health, and sexual function.

Quick summary

["Free testosterone helps assess hormone balance and potential hormone-related health concerns."]

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

Key facts at a glance

LOINC
27858-0
Short code
LH sp7 p chal SerPl-aCnc
Synonyms
LH sp7 p chal SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
1.5
Ref high
9
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83002
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 this test to evaluate hormone levels, especially if you have symptoms like low libido, fatigue, or changes in body hair. It can also help diagnose conditions like hypogonadism (low testosterone) or Cushing’s syndrome (high testosterone).

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if your lab uses a specific method. Avoid smoking or consuming alcohol for 24 hours before testing.

How the Test Works

A blood sample is taken from a vein in your arm. The sample is processed to separate serum or plasma, where free testosterone is measured using a sensitive immunoassay technique.

What the Results Mean

Results are compared to general reference ranges for free testosterone, but individual needs vary. Your provider will interpret results in the context of your symptoms and overall health.

Reference range

Follicular: 1.5-9.0 mIU/mLN/A

Specimen: serum

For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Free testosterone is a critical marker for male hormone function. Low levels may indicate conditions like pituitary disorders or androgen deficiency, while elevated levels could signal tumors or other hormonal imbalances. Regular monitoring helps manage conditions like infertility or metabolic disorders.

Short name

Free testosterone level

Frequently asked questions

How long does it take to get my results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your provider will contact you once they’re ready.
Can I eat or drink before this test?
Check with your provider about fasting requirements, but generally, you can eat a light meal or snack beforehand unless instructed otherwise.
Does this test require a referral?
No referral is typically needed for this test, but confirm with your healthcare provider if it’s part of a broader evaluation.
  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