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Testosterone, Total (Serum/Plasma)

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

This test measures the total amount of testosterone, a key hormone in men and women that affects energy, mood, muscle mass, and sexual function.

Quick summary

["Your total testosterone levels help doctors assess hormone balance and diagnose conditions like low testosterone or hormonal imbalances."]

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

Key facts at a glance

LOINC
17692-5
Short code
Testost 45M p chal SerPl-mCnc
Synonyms
Testost 45M p chal SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.5
Ref high
12
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84436
SNOMED
302345006
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?

Doctors may order a total testosterone test to evaluate symptoms such as low libido, fatigue, or changes in body hair. It can also be used in fertility assessments, before surgeries (like prostate removal), or to monitor hormone treatments.

Who Might Need This Test?

Men with symptoms like low energy, reduced sex drive, or unexplained muscle loss may need this test. Women with irregular periods, mood swings, or unusual hair growth might also be tested, especially if hormonal imbalances are suspected.

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 doctor specifies it. Avoid heavy exercise or smoking just before testing.

What Happens During the Test?

A healthcare provider will draw blood from a vein in your arm. The sample is sent to a lab for analysis using a high-performance liquid chromatography (hplc) method to measure testosterone concentration accurately.

Reference range

Adult: 4.5-12.0 μg/dLN/A

Specimen: serum

Take your thyroid medication after the blood draw if applicable. No fasting required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Testosterone

Frequently asked questions

What does a low testosterone level mean?
Low testosterone can cause symptoms like fatigue, reduced muscle strength, mood changes, or low sex drive. It may also affect bone density or cause erectile difficulties in men. Your doctor will discuss next steps based on your symptoms and test results.
What does a high testosterone level mean?
High testosterone can lead to symptoms like acne, excessive body hair growth (hirsutism), or mood swings. In women, it might cause irregular periods or voice changes. Further evaluation could be needed to rule out conditions like polycystic ovary syndrome (PCOS) or tumors.
How often should I get this test?
Your doctor will determine how often to retest based on your symptoms, age, and medical history. For example, men with suspected low testosterone might get follow-up tests every 6–12 months, while women with hormonal concerns may need more frequent monitoring.
  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