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Prostate-Specific Antigen (PSA) in Serum

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

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

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
87399-2
Short code
PTV Spec Ql Cult
Synonyms
PTV Spec Ql Cult
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
CPT
85610
SNOMED
396252006
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 Might Be Ordered

Your doctor may recommend a PSA test to monitor symptoms like urinary changes, pain in the pelvic area, or if you have a family history of prostate cancer. It can also be used during routine check-ups for men at higher risk.

What to Expect During the Test

A simple blood sample is taken from a vein in your arm. You’ll typically feel a small pinch, but it’s quick and doesn’t require special preparation. No fasting is needed unless specified by your provider.

How Results Are Interpreted

PSA levels alone don’t diagnose prostate cancer—they’re part of a broader evaluation. Your doctor will consider your age, symptoms, and other test results. Very low levels might suggest benign conditions, while very high levels may raise concerns.

Common Reasons for Abnormal Results

Elevated PSA can occur with prostate inflammation (prostatitis), benign prostatic hyperplasia (BPH), or prostate cancer. Low levels may indicate conditions like prostate shrinkage or certain medications.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: serum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PSA Level

Frequently asked questions

What causes PSA levels to change?
PSA levels can fluctuate due to factors like age, recent ejaculation (within 2 days), prostate inflammation, infections, or certain medications. Stress or exercise may also temporarily affect results.
How often should PSA testing be done?
The frequency depends on your age, health history, and risk factors. For men without symptoms, guidelines often recommend starting at age 50 (or earlier if at higher risk). Regular monitoring may be advised if you’ve had a previous PSA test or prostate issues.
Can diet or supplements affect PSA levels?
Some studies suggest certain foods (like cruciferous vegetables) or supplements (like selenium) may influence PSA levels, but evidence is mixed. Always discuss potential dietary changes with your doctor before making significant adjustments.
  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