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Prostate-Specific Antigen (PSA) in Serum or Plasma

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

This test measures the amount of prostate-specific antigen, a protein produced by the prostate gland, in your blood. It helps doctors assess prostate health and check for potential issues like benign prostatic hyperplasia (BPH) or prostate cancer.

Quick summary

["PSA levels can guide discussions about prostate health, but they’re not definitive on their own."]

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

Key facts at a glance

LOINC
53764-7
Short code
PSA Pnl SerPl
Synonyms
PSA Pnl SerPl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
4
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84153
SNOMED
39392002
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 Is PSA Used For?

PSA is primarily used to monitor prostate health, especially in men at higher risk for prostate cancer. It can also help track changes in prostate size or function, such as during treatments for BPH or prostate cancer.

How Is This Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is then sent to a lab for testing. The test can be done on either serum (liquid part of blood after clotting) or plasma (liquid part of blood without clotting).

Why Might You Need This Test?

Your doctor may recommend a PSA test if you have symptoms like urinary issues, pain in the pelvic area, or if you’re at higher risk for prostate problems. It’s also used as part of routine screening in certain cases.

What Do Results Mean?

PSA levels alone don’t diagnose prostate cancer—they’re part of a broader evaluation. Higher levels may raise concerns, but they can also be influenced by factors like age, prostate inflammation, or recent prostate exams.

Reference range

Normal: <4.0 ng/mLN/A

Specimen: serum

No special preparation required. For PSA, avoid sexual activity for 24-48 hours before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PSA Level

Frequently asked questions

How often should I get a PSA test?
The frequency depends on your age, medical history, and risk factors. For most men, the U.S. Preventive Services Task Force recommends against routine PSA screening in men under 55. Discuss with your doctor about personalized timing, especially if you have a family history of prostate cancer or other risk factors.
What are the normal ranges for PSA?
There’s no single ‘normal’ PSA range. Levels vary by age, health, and other factors. Your doctor will compare your result to your own baseline and consider your overall health. Very low levels can also signal potential issues, like prostate enlargement or inflammation.
Can diet or other lifestyle factors affect PSA levels?
Yes, certain foods, medications, or recent prostate exams (like a digital rectal exam) can temporarily raise PSA levels. Avoiding such triggers for a few weeks before testing can help get a more accurate reading.
  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