Prostate-Specific Antigen (PSA) Test

The Prostate-Specific Antigen (PSA) test is a blood test used to measure the level of PSA, a protein produced by the prostate gland, in the blood. The test is primarily used to screen for prostate cancer and monitor patients with a history of prostate cancer.

What is PSA?

PSA is a protein produced by the prostate gland, a small gland in men that produces fluid for semen. A small amount of PSA normally leaks into the bloodstream. However, certain conditions, such as prostate cancer, can cause more PSA to leak into the blood.

How is the PSA test performed?

The PSA test is a simple blood test that requires a sample of blood to be drawn from a vein in the arm. The blood sample is then sent to a laboratory for analysis, where the level of PSA is measured.

What are the types of PSA tests?

There are several types of PSA tests, including:

• Total PSA (tPSA) test: Measures the total amount of PSA in the blood.
• Free PSA (fPSA) test: Measures the amount of PSA that is not bound to other proteins in the blood.
• PSA velocity (PSAV) test: Measures the rate of change of PSA levels over time.
• PSA density (PSAD) test: Measures the level of PSA per unit volume of prostate tissue.

What are the normal PSA levels?

Normal PSA levels vary depending on age and other factors. In general, a PSA level of:

• 0-2.5 ng/mL is considered low risk for prostate cancer.
• 2.6-4 ng/mL is considered intermediate risk for prostate cancer.
• 4-10 ng/mL is considered high risk for prostate cancer.
• Above 10 ng/mL is considered very high risk for prostate cancer.

What are the limitations of the PSA test?

The PSA test has several limitations, including:

• False positives: Elevated PSA levels can be caused by non-cancerous conditions, such as prostatitis or benign prostatic hyperplasia (BPH).
• False negatives: Some prostate cancers may not produce enough PSA to raise the blood level.
• Lack of specificity: The PSA test cannot distinguish between different types of prostate cancer or other conditions that affect the prostate gland.

What are the risks and benefits of the PSA test?

The PSA test has both benefits and risks, including:

• Benefits: Early detection of prostate cancer, monitoring of patients with a history of prostate cancer, and guidance for treatment decisions.
• Risks: False positives, false negatives, overdiagnosis, and overtreatment of slow-growing tumors that may not cause symptoms or affect quality of life.

Frequently Asked Questions (FAQs)

What is a PSA test?
Blood test measuring prostate-specific antigen levels.

Why is a PSA test done?
To screen for prostate cancer and monitor treatment.

How is a PSA test performed?
Blood sample taken from a vein in the arm.

What is a normal PSA level?
Typically less than 4 nanograms per milliliter (ng/mL).

What does an elevated PSA level mean?
May indicate prostate cancer, but not always.

Can a PSA test detect all prostate cancers?
No, some prostate cancers may not produce PSA.

How often should a PSA test be done?
Typically annually for men over 50 or at high risk.

Are there any risks to a PSA test?
Minimal, such as bruising or bleeding at the needle site.

Can certain factors affect PSA levels?
Yes, such as prostate enlargement, infection, or recent ejaculation.

What happens if a PSA test result is abnormal?
Further testing, such as a biopsy, may be recommended.