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Home > Health Library > Prostate-Specific Antigen (PSA) Test
A prostate-specific antigen (PSA) test measures the amount of prostate-specific antigen in the blood. PSA is released into a man's blood by his prostate gland. Healthy men have low amounts of PSA in the blood. The amount of PSA in the blood normally increases as a man's prostate enlarges with age. PSA may increase because of inflammation of the prostate gland (prostatitis) or prostate cancer. An injury, a digital rectal exam, or sexual activity (ejaculation) may also briefly raise PSA levels.
The prostate-specific antigen (PSA) test is done to:
Do not ejaculate during the 2 days before your PSA blood test, either during sex or masturbation. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean.
A health professional uses a needle to take a blood sample, usually from the arm.
When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.
There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.
Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.
Because normal PSA levels seem to increase with age, age-specific ranges may be used. But the use of age-specific ranges is controversial, and some doctors prefer to use one range for all ages. For this reason, it is important to discuss your test results with your doctor.
A PSA level within the normal ranges does not mean that prostate cancer is not present. Some men who have prostate cancer have normal PSA levels.
High levels don't always mean that prostate cancer is present. PSA levels may be high if the prostate gland is enlarged (benign prostatic hyperplasia, or BPH) or inflamed (prostatitis).
A follow-up test that measures free prostate-specific antigen (free PSA) may be used to see if a prostate biopsy should be done to check for cancer. Free PSA is the percent of prostate-specific antigen that is not attached to proteins in the blood. The lower a man's free PSA percentage, the more likely he is to have prostate cancer.
A man with a total PSA between 4 and 10 ng/mL may have a test to find out his free PSA, to see if cancer is likely to be present. This test can be very useful if he had a negative prostate biopsy in the past but still has a high total PSA.
Current as of:
December 17, 2020
Author: Healthwise StaffMedical Review: E. Gregory Thompson MD - Internal MedicineKathleen Romito MD - Family MedicineChristopher G. Wood MD, FACS - Urology, Oncology
Current as of: December 17, 2020
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Kathleen Romito MD - Family Medicine & Christopher G. Wood MD, FACS - Urology, Oncology
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