Skip to content

Prostate-Specific Antigen (PSA) in Serum by Immunoassay (Screening)

Published: August 9, 2026Updated: August 17, 2026

This test measures the level of prostate-specific antigen (PSA) in your blood, a protein produced by both healthy and cancerous prostate cells. It helps doctors assess your risk for prostate cancer or monitor existing conditions.

Quick summary

["PSA screening can help detect early signs of prostate issues, including cancer."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
97318-0
Short code
EPEC DNA Stl Ql NAA+probe
Synonyms
EPEC DNA Stl Ql NAA+probe
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
CPT
84484
SNOMED
302774002
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like frequent urination, pain during urination, or if you’re at higher risk for prostate problems due to age, family history, or other health factors. It’s also used as a follow-up for men with known prostate concerns.

What to Expect Before the Test

No special preparation is needed, but avoid ejaculation for 2 days before the test if possible. Drink plenty of water the day before to help your blood flow smoothly. Wear comfortable clothing and plan to stay for about 15 minutes.

What Happens During the Test

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

PSA levels alone don’t diagnose prostate cancer—they’re part of a broader evaluation. Higher levels may raise concerns, prompting further testing like a digital rectal exam or biopsy. Your doctor will discuss results in the context of your overall health and symptoms.

Reference range

Adult: 10-40 U/LN/A

Specimen: stool

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PSA Screen

Frequently asked questions

What causes PSA levels to change?
PSA levels can be influenced by factors like age, recent ejaculation, prostate infections, or medical procedures. For example, ejaculation or a prostate exam can temporarily spike PSA levels. If you’ve had any recent prostate-related activity, let your doctor know so they can adjust interpretation accordingly.
How often should I get this test?
The frequency depends on your age, symptoms, and risk factors. Men over 50 may start discussions with their doctor about screening every 1–2 years. Those with a family history of prostate cancer or other risk factors might need more frequent testing. Your doctor will tailor recommendations to your needs.
Can I lower my PSA levels naturally?
While diet and lifestyle changes like reducing red meat, fatty foods, or managing obesity may support overall prostate health, they don’t directly lower PSA levels. Focus on a balanced diet, staying hydrated, and avoiding smoking. Always consult your doctor before making major lifestyle changes.
  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 17, 2026. · Read our editorial policy