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Prostate-specific antigen; Prostate cancer screening test
PSA stands for prostate-specific antigen. It is a protein produced by prostate cells.
This article discusses the blood test to measure the amount of PSA in a man's blood. The PSA test is done to help diagnose and follow prostate cancer in men.
Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.
Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
Men should not ejaculate for at least 48 hours before the PSA test is done. Doing so may cause a false rise in PSA levels.
Make sure your doctor knows all the medications you're taking. Some drugs may cause your PSA levels to be falsely low. These include finasteride, dutasteride, saw palmetto use, and antiandrogen drugs, such as flutamide, nilutamide, and bicalutamide.
No other special preparation is usually needed.
When the needle is inserted to draw blood, some people feel moderate pain while others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a bruise.
Reasons for a PSA test:
For information about prostate cancer screening, see the "Considerations" section below.
American Urological Association.
Lin K, Lipsitz R, Miller T, Janakiraman S; U.S. Preventive Services Task Force. Benefits and harms of prostate-specific antigen screening for prostate cancer: an evidence update for the U.S. Preventive Services Task Force. Ann Intern Med. 2008;149:192-199.
Lim LS, Sherin K; ACPM Prevention Practice Committee. Screening for prostate cancer in U.S. men ACPM position statement on preventive practice. Am J Prev Med. 2008;34:164-170.
Walsh PC, DeWeese TL, Eisenberger MA. Clinical practice. Localized prostate cancer. N Engl J Med. 2007;357:2696-2705.
Walter LC, Bertenthal D, Lindquist K, Konety BR. PSA screening among elderly men with limited life expectancies. JAMA. 2006;296:2336-2342.
Wolf AM, Wender RC, Etzioni RB, Thompson IM, D'Amico AV, Volk RJ, et al. American Cancer Society guideline for the early detection of prostate cancer: update 2010. CA Cancer J Clin. 2010;60:70-98.
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