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Prostate-Specific Antigen (PSA) in Serum by Immunoassay (with Probe Qualifier)

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

This test measures the level of prostate-specific antigen (PSA), a protein produced by both healthy and cancerous prostate cells. It helps doctors assess prostate health, detect prostate cancer, or monitor treatment progress.

Quick summary

["PSA levels can signal prostate issues, guiding next steps in care."]

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

Key facts at a glance

LOINC
112395-9
Short code
T palldm DNA Skin Ql NAA+probe
Synonyms
T palldm DNA Skin 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 Matters

PSA is commonly used to screen for prostate cancer, though it can also indicate benign conditions like prostate inflammation or enlargement. Elevated PSA may prompt further evaluation, including imaging or biopsies.

What to Expect Before the Test

No special preparation is needed, but avoid ejaculation for 2–3 days before testing. If you’re on medications affecting PSA (e.g., finasteride), inform your provider.

What the Results Mean

Results are interpreted in context of your symptoms, age, and medical history. While PSA alone isn’t definitive for cancer, it’s a key part of a broader evaluation. Your doctor will discuss findings with you.

Common Reasons for Testing

Doctors order PSA tests for routine screening (typically starting at age 50/45), symptoms like urinary changes, or after prostate procedures. It may also monitor treatment response in prostate cancer.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PSA Blood Test

Frequently asked questions

How long does it take to get PSA test results?
Results are typically available within 1–3 business days, depending on lab processing times. Your doctor will contact you with findings or schedule a follow-up if needed.
Can PSA levels change with diet or exercise?
Dietary factors like cruciferous vegetables (e.g., broccoli) or supplements (e.g., zinc) may slightly affect PSA, but the impact is usually minor. Exercise and weight management support overall prostate health but don’t directly alter PSA levels.
What if my PSA level is abnormal?
If your PSA is elevated, your doctor may recommend additional tests (e.g., digital rectal exam, imaging, or a biopsy) to investigate further. They’ll discuss the next steps with you based on your individual situation.
  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