Written by:Fact check:

Overview

What Is a PSA Blood Test?

PSA stands for prostate-specific antigen, a protein produced mainly by prostate tissue. A PSA blood test measures the amount of this protein in a blood sample. The result can support prostate cancer screening or evaluation of prostate problems, but the measurement alone is not a diagnosis of cancer.

When It Is Needed

Reasons a Clinician May Order The Test

A clinician may order a PSA test when you have urinary symptoms, an abnormal prostate examination, or another concern about prostate disease. It may also be used to monitor someone after prostate cancer treatment. PSA screening for people without symptoms is an individual decision based on factors such as age, family history, race or ethnicity, inherited risk, overall health, and the possible benefits and harms of follow-up.

Preparation

How to Prepare for a PSA Blood Test

Fasting is usually not needed for a PSA blood test, but follow the instructions from the ordering laboratory. Tell the clinician about medicines such as finasteride or dutasteride, which can affect PSA levels, and mention any recent prostate evaluation or treatment.

  • Ask the testing service whether to avoid ejaculation or vigorous cycling before the test.
  • Tell the clinician about urinary symptoms, a suspected infection, or prostatitis.
  • Report recent catheterization, prostate biopsy, cystoscopy, or other prostate procedures.
  • Do not stop prescribed medicines unless the clinician tells you to.

During the Test

What Happens During a PSA Blood Test?

A PSA blood test is completed during one appointment. A healthcare professional cleans the skin, inserts a small needle into a vein, collects blood into a tube, removes the needle, and applies pressure and a bandage to the site.

  • The needle may cause a brief pinch or stinging sensation.
  • Mild bruising or tenderness can occur at the collection site.
  • The blood draw itself usually takes only a few minutes.
  • The sample is sent to a laboratory for PSA measurement.

Risks

What Are the Risks of a PSA Blood Test?

  • The puncture site may be briefly painful, bruised, or tender.
  • A small amount of bleeding or, rarely, infection can occur at the puncture site.
  • Some people feel light-headed during or after the blood draw.
  • An elevated result can lead to repeat testing or further procedures even when cancer is not present.
  • PSA screening can find slow-growing cancer that might never have caused symptoms.

Results

Understanding PSA Blood Test Results

The report gives a PSA concentration, commonly shown in nanograms per milliliter (ng/mL). Laboratories may provide different reference information, and there is no single PSA value that proves or rules out prostate cancer. Your clinician interprets the PSA reading with your symptoms, examination findings, risk factors, and other test results.

How PSA levels are interpreted

A lower, borderline, or rising result may have different meanings depending on age, prostate size, infection or inflammation, recent procedures, medicines, and the change over time. After an abnormal result, possible next steps include checking for temporary causes, repeating the PSA, reviewing the trend, using additional blood or urine tests, obtaining imaging, or considering a biopsy when clinically appropriate. A very high PSA result needs prompt review by a clinician, but it should not be self-interpreted in isolation; even a result such as 56 requires assessment of the complete clinical picture.

Diseases & Conditions

2 topics