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Prostate-Specific Antigen (PSA) in Serum/Plasma

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

This test measures the level of prostate-specific antigen, a protein produced by both normal and cancerous prostate cells, in your blood. It helps assess prostate health and detect potential issues like prostate cancer.

Quick summary

["PSA tests are used to monitor prostate health and guide decisions about further medical evaluation."]

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

Key facts at a glance

LOINC
85339-0
Short code
PR Ag Br ca spec Ql ImStn
Synonyms
PR Ag Br ca spec Ql ImStn
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immune-stain
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 Matters

Prostate-specific antigen (PSA) is a protein made by both healthy and unhealthy prostate cells. While PSA levels can rise with age or certain conditions like benign prostatic hyperplasia (BPH), they may also signal prostate cancer. This test is often used in screening, monitoring, or diagnosing prostate health issues.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid ejaculation for 48 hours before the test if it’s part of a screening or monitoring plan. Your blood will be drawn from a vein, typically in your arm, by a healthcare professional.

What the Results Mean

Results are interpreted based on your age, overall health, and medical history. A higher-than-normal PSA level may prompt further testing, such as a digital rectal exam or a biopsy, to investigate potential causes. Results alone don’t confirm a diagnosis of prostate cancer.

Common Causes of Abnormal PSA Levels

PSA levels can be influenced by factors like prostate inflammation, infections, prostate enlargement, or recent prostate procedures. Smoking, obesity, or certain medications may also affect PSA levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

PSA Level

Frequently asked questions

What does a high PSA level indicate?
A high PSA level can signal potential prostate issues, including inflammation, infection, or cancer. However, it’s not definitive. Your doctor will consider other factors, such as symptoms, physical exam, and additional tests, to determine the next steps.
How often should PSA testing be done?
The frequency of PSA testing depends on your age, risk factors, and overall health. The U.S. Preventive Services Task Force recommends against routine PSA screening for men under 55 due to potential harms. Discuss with your doctor whether testing is appropriate for you.
Can lifestyle changes affect PSA levels?
Yes, lifestyle factors like smoking, diet, and exercise can influence PSA levels. Avoiding smoking, maintaining a healthy weight, and eating a balanced diet may help support prostate health.
  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