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Total Testosterone (Serum)

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

This test measures the total amount of testosterone, a key male sex hormone, in your blood. Testosterone plays a role in muscle development, bone health, and overall male reproductive function.

Quick summary

["Your testosterone levels help determine if you have healthy hormone balance, especially important for men and women."]

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

Key facts at a glance

LOINC
6891-6
Short code
Testosterone.free+WB MFr SerPl
Synonyms
Testosterone.free+WB MFr SerPl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
300
Ref high
1000
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84403
SNOMED
33790003
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 This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like low energy, reduced sex drive, or changes in body hair. It could also be part of evaluations for infertility, hormonal imbalances, or conditions like hypogonadism (low 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 test if it’s part of a broader metabolic panel. Wear comfortable clothing for blood draw.

How the Test Works

A small blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s analyzed to measure testosterone levels using an immunoassay method.

What the Results Mean

Results are compared to general reference ranges for your age and sex. Low levels may indicate conditions like hypogonadism, while high levels could suggest hormonal imbalances or other health issues.

Reference range

Adult males: 300-1000 ng/dLN/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.

◆Associated findings1

Short name

Total Testosterone

Frequently asked questions

What causes low testosterone levels?
Low testosterone can result from aging, certain medications, chronic illnesses, or conditions affecting the pituitary or testes. Lifestyle factors like obesity, smoking, or poor sleep may also play a role.
What should I do if my testosterone levels are low?
If your results are below normal, discuss them with your provider. Possible next steps include lifestyle changes (diet, exercise), hormone therapy, or further testing to identify the underlying cause.
Can diet or exercise affect testosterone levels?
Yes, maintaining a healthy weight, eating zinc-rich foods, and engaging in strength training may support natural testosterone production. Stress reduction and adequate sleep also help hormone balance.
  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