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Prostate-Specific Antigen (PSA) in Plasma by Immunoassay (CLIA)

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

This test measures the level of prostate-specific antigen (PSA), a protein produced by prostate cells, in your blood plasma. It helps assess prostate health and detect potential issues like prostate cancer or inflammation.

Quick summary

["PSA blood tests are commonly used to monitor prostate health and guide decisions about further evaluation."]

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

Key facts at a glance

LOINC
100749-1
Short code
Lp-SG1 Spec Ql NAA+probe
Synonyms
Lp-SG1 Spec 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 Is This Test Done?

Your healthcare provider may order this test to check for prostate problems, such as an enlarged prostate, infection, or cancer. It’s often used in screening, follow-up care, or monitoring treatment progress for prostate conditions.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid ejaculation for 2–7 days before the test if it’s part of a screening or monitoring plan. Drink plenty of water to help with blood collection.

What Happens During the Test?

A small amount of blood is drawn from a vein in your arm by a healthcare professional. The blood is then processed to separate plasma for testing.

What Are Possible Results?

Results are reported in nanograms per milliliter (ng/mL). Higher than expected levels may signal prostate issues, but results depend on your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

PSA levels can vary widely among individuals. While elevated PSA may raise concerns about prostate cancer or other conditions, it’s not definitive on its own. Your provider will consider the result alongside other factors, such as age, family history, and symptoms, to guide further testing or treatment decisions.

Short name

PSA Plasma

Frequently asked questions

What does a PSA test measure?
A PSA test measures the amount of PSA protein in your blood. PSA is produced by both healthy and diseased prostate cells, so it can indicate potential issues like inflammation, infection, or cancer.
How long does it take to get PSA test results?
Results are typically available within 1–3 business days after the test is completed, depending on your lab’s processing time.
Can diet or medications affect PSA levels?
Certain medications (e.g., finasteride, dutasteride) or conditions (e.g., prostate infection, urinary tract issues) may temporarily alter PSA levels. Your provider will discuss any potential influences with you.
  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