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Prostate-specific antigen (PSA) is a protein produced by prostate cells.
The PSA test is done to help diagnose and follow prostate cancer in men.
Prostate-specific antigen; Prostate cancer screening test
A blood sample is needed.
Make sure your doctor knows all the medicines you are taking. Some drugs cause your PSA level to be falsely low.
No other special preparation is usually needed.
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise. These soon go away.
Reasons for a PSA test:
Measuring the PSA level can increase the chance of finding prostate cancer when it is very early. But the value of PSA screening for prostate cancer is debated. No single answer fits all men.
Before having the test, discuss with your doctor both the reasons to have and not to have a PSA test.
If you choose to be tested, the PSA is most often done every year to screen men:
The PSA test result cannot diagnose prostate cancer. Only a prostate biopsy can diagnose this cancer.
Your doctor will look at your PSA result and consider your age, ethnicity, medicines you are taking, and other things to decide whether your PSA is normal and whether you need more tests.
A normal PSA level is considered to be 4.0 ng/ml (nanograms per milliliter of blood).
A high PSA level has been linked to an increased chance of having prostate cancer.
PSA testing is an important tool for detecting prostate cancer, but it is not foolproof. Other conditions can cause a rise in PSA, including:
Your doctor will think about the following things when deciding on the next step:
Men at high risk may need to have more tests. Your doctor may recommend:
If you have been treated for prostate cancer, the PSA level can show if treatment is working or if the cancer has come back. Often, PSA level rises before there are any symptoms, sometimes months or years beforehand.
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
American Urological Association Education and Research, Inc. PSA testing for the pretreatment staging and posttreatment management of prostate cancer: 2013 Revision of 2009 Best Practice Statement. Linthicum, MD: American Urological Association Education and Research, Inc. 2013. Available at: http://www.auanet.org/common/pdf/education/clinical-guidance/Prostate-Specific-Antigen.pdf. Accessed October 3, 2013.
Getzenberg RH, Partin AW. Prostate cancer tumor markers. In: Wein AJ, Kavoussi LR, Novick AC, et al., eds. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 98.
U.S. Preventive Services Task Force. Screening for prostate cancer. Available at: http://www.uspreventiveservicestaskforce.org/prostatecancerscreening/prostatefinalrs.htm. Accessed July 26, 2013.