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Prostate-Specific Antigen (PSA) by Immunoassay (Screening Probe)

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

This test measures a protein produced mainly by prostate cells to help check for prostate health or early signs of prostate cancer.

Quick summary

["PSA levels can help guide discussions about prostate health or potential testing for cancer."]

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

Key facts at a glance

LOINC
61399-2
Short code
K pnm DNA Spec Ql NAA+probe
Synonyms
K pnm DNA Spec 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

Why This Test Is Done

Doctors may order a PSA test to monitor symptoms of prostate issues, screen for prostate cancer in certain groups, or evaluate changes in prostate health over time. It’s often used alongside other tests or exams, like a digital rectal exam.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid ejaculation for 2–4 days before testing to get a more accurate result. Wear comfortable clothing and plan to stay for about 15 minutes while the blood is drawn.

What Happens During the Test

A healthcare provider will insert a small needle into a vein in your arm to collect a blood sample. You may feel a brief pinch, but it usually doesn’t cause significant discomfort. The blood is then sent to a lab for analysis.

What the Results Mean

PSA results alone don’t diagnose prostate cancer, but they can signal whether further testing is needed. Higher-than-normal levels may prompt additional evaluations, such as imaging or a biopsy, to explore potential concerns.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

PSA Screening

Frequently asked questions

What Is a Normal PSA Level?
There’s no single ‘normal’ PSA level for everyone. Results can vary based on age, overall health, and other medical conditions. Discuss your results with your doctor to understand what they mean for you.
Can PSA Levels Change Over Time?
Yes, PSA levels can fluctuate due to factors like age, prostate inflammation, infections, or medications. Regular monitoring may help track changes, but it’s important to work with your healthcare team to interpret results accurately.
Does This Test Detect All Types of Prostate Cancer?
No, PSA tests detect a protein produced by prostate cells, but they’re not specific to cancer. Some cancers may not raise PSA levels, and other conditions (like benign prostatic hyperplasia) can also affect PSA. Further testing is often needed for diagnosis.
  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