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Prostate-Specific Antigen (PSA) in Fluid by Immunoassay (Quantitative)

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

This test measures the amount of prostate-specific antigen (PSA) in your fluid sample. PSA is a protein produced by both healthy and cancerous prostate cells.

Quick summary

["PSA helps doctors assess prostate health, including detecting early signs of prostate cancer or other prostate issues."]

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

Key facts at a glance

LOINC
106587-9
Short code
C tropicls DNA Fld Ql NAA+n-prb
Synonyms
C tropicls DNA Fld Ql NAA+n-prb
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
non-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 Is Done

Doctors may order this test to monitor prostate health, especially if you have symptoms like frequent urination, pain during urination, or an abnormal prostate exam. It can also be used during screening for prostate cancer or after treatment to check for recurrence.

What to Expect Before the Test

You may be asked to avoid ejaculation for 2–3 days before the test, as it can temporarily raise PSA levels. If your sample is blood, you might need to fast for a few hours, but if it’s urine or another fluid, no special preparation is usually required.

What the Results Mean

PSA levels vary by age, health, and other factors. While higher levels can signal prostate issues, including cancer, they can also be influenced by benign conditions like an enlarged prostate (BPH). Your doctor will interpret results in the context of your medical history and symptoms.

Common Causes of Abnormal Results

Elevated PSA may occur with prostate cancer, infections, inflammation, or benign growths. Lower-than-expected levels might suggest prostate tissue loss (e.g., from surgery or radiation) or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PSA Level Test

Frequently asked questions

What might cause my PSA levels to be higher than expected?
Higher-than-normal PSA can result from prostate cancer, but it can also be raised by benign conditions like an enlarged prostate, infections, or recent ejaculation. Your doctor will review your full medical picture to determine the cause.
How often should I get this test?
The frequency depends on your age, symptoms, and risk factors. Men over 50 with no symptoms may start screening at age 55, while those with higher risk (family history, race) may begin earlier. Your doctor will guide you on timing.
Can PSA levels change over time?
Yes, PSA levels can fluctuate due to age, prostate size, infections, or treatments. Regular monitoring helps track changes, but it’s not a standalone test for diagnosis—it’s often used alongside other exams like a digital rectal exam or biopsy.
  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