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Prostate-Specific Antigen (PSA) with Free PSA Fraction and Ratio

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

This blood test measures levels of prostate-specific antigen, a protein produced by the prostate gland, to help assess prostate health.

Quick summary

["PSA testing helps detect potential prostate issues, including benign enlargement or early cancer."]

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

Key facts at a glance

LOINC
43216-1
Short code
C pn+psitt DNA Throat Ql NAA+probe
Synonyms
C pn+psitt DNA Throat Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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

What PSA Levels Indicate?

PSA levels vary based on age, health, and medical history. Higher levels may suggest prostate concerns, but they’re not definitive on their own. Free PSA helps distinguish between benign conditions and prostate cancer.

Why Is Free PSA Used?

Free PSA (the portion not bound to other proteins) is less likely to be elevated in prostate cancer than total PSA. The free PSA ratio (free PSA ÷ total PSA) can help guide further evaluation, especially in men with borderline PSA levels.

How Is This Test Performed?

A blood sample is drawn from a vein, typically in your arm. The test measures total PSA and the free PSA fraction using immunoassay methods to detect and quantify the protein.

When Might You Need This Test?

Doctors may order PSA testing to monitor prostate health, screen for prostate cancer (especially in high-risk groups), or evaluate symptoms like urinary changes or pain.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: PSA Testing Plays a Key Role in Prostate Health Monitoring

Short name

PSA Test

Frequently asked questions

How often should I get this test?
Frequency depends on your age, symptoms, and risk factors. Younger men may get baseline tests, while older men or those with risk factors may need more frequent monitoring. Always follow your healthcare provider’s recommendations.
What do my PSA results mean?
Results are interpreted with your overall health in mind. While higher PSA levels may raise concerns, they don’t always indicate cancer. Your doctor will consider the total PSA, free PSA ratio, and clinical context to guide next steps.
Can lifestyle changes affect PSA levels?
Yes, factors like exercise, diet, and certain medications may influence PSA levels. Avoiding strenuous activity or sexual activity 2–3 days before testing can help ensure more accurate results.
  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