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Testosterone, Serum or Plasma Substance Concentration

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

This test measures the amount of testosterone, a key male sex hormone, in your blood. Testosterone helps regulate muscle mass, bone density, and sexual function.

Quick summary

["Testosterone levels can influence energy, mood, and reproductive health in both men and women."]

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

Key facts at a glance

LOINC
10631-0
Short code
Testost Smn-sCnc
Synonyms
Testost Smn-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Might You Need This Test?

Your healthcare provider may order a testosterone test to check for hormonal imbalances, evaluate symptoms like low energy, low libido, or irregular menstrual cycles, or monitor conditions like hypogonadism or Cushing’s syndrome. It can also be part of fertility assessments or evaluations for delayed puberty.

What Does the Test Involve?

A blood sample is taken from a vein in your arm. The blood is then sent to a lab for analysis using an immunoassay method to measure testosterone concentration. You may feel slight discomfort, but it usually takes a few minutes.

What to Expect Before or After the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if instructed. After the test, you can resume normal activities. Results may take a few days to a week to receive.

What the Results Might Mean

Testosterone levels can vary based on age, sex, and health status. Low or high levels may signal underlying health concerns that your provider will discuss with you during your follow-up.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Testosterone Levels and Health

Short name

Testosterone Level

Frequently asked questions

How is testosterone measured in this test?
This test measures testosterone concentration in your blood using an immunoassay method, which detects and quantifies the hormone’s presence. The result reflects your current testosterone levels in the serum or plasma.
What are common reasons for abnormal testosterone levels?
Abnormal testosterone levels can be caused by conditions like pituitary disorders, kidney or liver disease, obesity, or certain medications. They may also appear in people with genetic disorders or those undergoing treatments like chemotherapy.
Can lifestyle factors affect testosterone levels?
Yes, lifestyle factors such as diet, exercise, stress, sleep quality, and substance use can influence testosterone levels. Maintaining a balanced diet, regular physical activity, and managing stress may support healthy hormone function.
  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