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Prostate-Specific Antigen (PSA) in Serum: Quantitative Probe Test

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

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

Quick summary

["PSA levels can indicate prostate health and help guide further medical evaluation."]

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

Key facts at a glance

LOINC
85325-9
Short code
PR+ cells NFr Br ca spec ImStn
Synonyms
PR+ cells NFr Br ca spec 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 Is Done

Doctors may order a PSA test to monitor prostate health, especially in men at higher risk for prostate cancer. It can also be used during follow-up after treatment or in cases of suspected prostate issues, such as an enlarged prostate (benign prostatic hyperplasia) or infection.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, which usually causes only mild discomfort. Avoid ejaculation for 2–4 days before testing if your doctor recommends it, as PSA levels can be temporarily affected by recent sexual activity.

What the Test Results Mean

PSA levels alone don’t diagnose prostate cancer, but they provide important information. Elevated levels may signal prostate issues, while lower levels might suggest other conditions. Your doctor will interpret results in the context of your medical history and symptoms.

Common Causes of Abnormal PSA Levels

PSA levels can rise due to prostate inflammation (prostatitis), an enlarged prostate, or prostate cancer. Other factors, such as age, recent ejaculation, or urinary tract infections, can also influence results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

PSA Serum

Frequently asked questions

How often should I get a PSA test?
The American Urological Association recommends PSA screening every 2–5 years for men aged 55–69, depending on risk factors like family history or ethnicity. Discuss this with your doctor, as guidelines vary by individual health and lifestyle.
Can PSA levels be affected by diet or supplements?
Some foods, like cruciferous vegetables (e.g., broccoli), or supplements (e.g., saw palmetto) may influence PSA levels, but the effect is usually mild. Your doctor may ask about recent diet or supplements if results seem unusual.
What if my PSA level is higher than expected?
A higher-than-normal PSA may prompt further testing, such as a digital rectal exam or additional imaging. Your doctor will guide next steps based on your symptoms, age, and overall 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