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Prostate-Specific Antigen (PSA) in Serum by Immunoassay

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

This test measures the level of prostate-specific antigen (PSA), a protein produced mainly by the prostate gland. PSA helps doctors assess prostate health, including detecting early signs of prostate cancer or benign prostate conditions.

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
86238-3
Short code
N men sg X xcbB Ct Spec Qn NAA+probe
Synonyms
N men sg X xcbB Ct Spec Qn 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 Matters

PSA is often used as part of routine or targeted prostate health screenings, especially in men at higher risk. It can help identify abnormalities that may require further evaluation, such as biopsies or additional imaging.

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. If you have a recent prostate procedure, your doctor may advise waiting before retesting.

Common Uses and Results

Elevated PSA levels may suggest conditions like prostate cancer, benign prostatic hyperplasia (BPH), or prostate inflammation. However, a single elevated result doesn’t confirm a diagnosis—it often prompts further testing.

Possible Causes of Abnormal Results

Other factors, such as age, recent ejaculation, urinary tract infections, or prostate surgery, can temporarily affect PSA levels. Your doctor will consider these factors when interpreting results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: PSA is a key biomarker for prostate health monitoring. While it’s not a perfect test, it plays a role in early detection and guiding follow-up care for men at risk of prostate issues.

Short name

PSA Blood Test

Frequently asked questions

What does a ‘normal’ PSA level mean for me?
There’s no single ‘normal’ PSA level—it varies by age, overall health, and individual risk factors. Your doctor will compare your result to your baseline and consider your medical history.
Can diet or supplements affect PSA levels?
Some foods (like cruciferous vegetables) or supplements (like zinc) may influence PSA, but the impact is usually small. Always discuss any changes with your doctor.
How often should I get this test?
Your doctor will determine frequency based on your age, symptoms, and risk factors. Regular screenings may start at age 50 (or earlier for higher-risk men).
  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