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PSA

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Also known as: Total PSA; Free PSA; Complexed PSA
Formal name: Prostate Specific Antigen

At a Glance

Why Get Tested?

To screen men for prostate cancer (although there is currently no consensus about using this test to screen asymptomatic men for prostate cancer), to help determine the necessity for a biopsy of the prostate, to monitor the effectiveness of treatment for prostate cancer, and to detect recurrence of prostate cancer

When to Get Tested?

When a man has symptoms suggestive of prostate cancer such as difficult, painful, and/or frequent urination; may also be ordered during and at regular intervals after prostate cancer treatment. There is continued debate among experts and national organizations over when and how often to order the PSA test to screen asymptomatic men. The frequency of prostate cancer screening is an individual decision that should be determined through discussion with your physician. (For specific details, see prostate cancer screening for Adults and Adults 50 and Up).

Sample Required?

A blood sample drawn from a vein in the arm

Test Preparation Needed?

Avoid ejaculation for 24 hours before sample collection as it has been associated with elevated PSA levels; the sample should also be collected prior to your doctor performing a digital rectal exam (DRE) and prior to (or several weeks after) a prostate biopsy.

The Test Sample

What is being tested?

Diagram of the prostatePSA is a protein produced primarily by cells in the prostate, a small gland that encircles the urethra in males and produces a fluid that makes up part of semen. Most of the PSA that the prostate produces is released into this fluid, but small amounts of it are also released into the bloodstream. PSA exists in two forms in the blood: free (not bound) and complexed (cPSA, bound to a protein). The most frequently used PSA test is the total PSA, which measures the sum of the free PSA and the cPSA in the blood. When a doctor orders a "PSA test," he is referring to a total PSA.

This test is used as a tumor marker to screen for and to monitor prostate cancer. It is a good tool but not a perfect one, and currently there is no consensus among experts on the usefulness of this test for screening asymptomatic men. Elevated levels of PSA are associated with prostate cancer, but they may also be seen with prostatitis and benign prostatic hyperplasia (BPH). Mild to moderately increased concentrations of PSA may be seen in those of African American heritage, and levels tend to increase in all men as they age.

PSA is not diagnostic of cancer. The gold standard for identifying prostate cancer is the prostate biopsy, collecting small samples of prostate tissue and identifying abnormal cells under the microscope. The total PSA test and digital rectal exam (DRE) are used together to help determine the need for a prostate biopsy. The goal of screening is to minimize unnecessary biopsies and to detect clinically significant prostate cancer while it is still confined to the prostate. The term clinically significant is important because while prostate cancer becomes relatively common in men as they age, many of the tumors are very slow-growing and this type of cancer is an uncommon cause of death. Doctors must try to both detect prostate cancer and to differentiate between slow-growing cases and prostate cancers that may grow aggressively and spread to other parts of the body (metastasize). Over-diagnosing and over-treatment are issues with which doctors are currently grappling. In some cases, the treatment can be worse than the cancer, with the potential for causing significant side effects, incontinence, and erectile dysfunction. The PSA test and DRE can detect most cases of prostate cancer, but they cannot, in general, predict the course of a person's disease.

Free PSA and cPSA tests can be ordered individually. The tests that measure them were developed to better differentiate between cancer-related and non-cancer-related PSA increases. Both of the tests operate on the principle that men with prostate cancer frequently have altered ratios of the two forms of PSA - decreased amounts of free PSA and increased amounts of cPSA.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

Ejaculation should be avoided for 24 hours before sample collection as it has been associated with elevated PSA levels. The sample should also be collected prior to the physician performing a digital rectal exam (DRE) and prior to (or several weeks after) a prostate biopsy.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

(2011 October 11) U.S. Preventive Services Task Force. Screening for Prostate Cancer: U.S. Preventive Services Task Force Recommendation Statement DRAFT [On-line information]. Available online at http://www.uspreventiveservicestaskforce.org/uspstf12/prostate/draftrecprostate.htm through http://www.uspreventiveservicestaskforce.org. Accessed May 2012.

Simon, S. (2012 May 21). Task Force Recommends Against Routine Prostate Cancer Screening. American Cancer Society. [On-line information]. Available online at http://www.cancer.org/Cancer/news/News/task-force-recommends-against-routine-prostate-cancer-screenin through http://www.cancer.org. Accessed May 2012.

(2012 May 29). U.S. Preventive Services Task Force Advises against PSA Screening. NCI Cancer Bulletin v9 (11). [On-line information]. Available online at http://www.cancer.gov/ncicancerbulletin/052912/page4 through http://www.cancer.gov. Accessed May 2012.

Norton, A. (2012 May 28). Doctors disagree on when to stop PSA screening. MedlinePlus Medical Encyclopedia from Reuters Health [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/news/fullstory_125648.html through http://www.nlm.nih.gov. Accessed May 2012.

(Updated 2012 March 28). National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC). Medical Tests for Prostate Problems [On-line information]. Available online at http://kidney.niddk.nih.gov/kudiseases/pubs/medtestprostate/ through http://kidney.niddk.nih.gov. Accessed May 2012.

Wiebe, C. (2012 May 29). Before PSA Screening, 'People Were Drowning.' Medscape Medical News from the American Urological Association (AUA) 2012 Annual Scientific Meeting [On-line information]. Available online at http://www.medscape.com/viewarticle/764659 through http://www.medscape.com. Accessed May 2012.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 795-798.

Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pp 500-501.

(Updated 22 May 2012). Centers for Disease Control and Prevention. Prostate Cancer - Screening. Available online at http://www.cdc.gov/cancer/prostate/basic_info/screening.htm through http://www.cdc.gov. Accessed June 2012. 

(Last Revised 5 March 2012). American Cancer Society. American Cancer Society Guidelines for the Early Detection of Cancer. Available online at http://www.cancer.org/Healthy/FindCancerEarly/CancerScreeningGuidelines/american-cancer-society-guidelines-for-the-early-detection-of-cancer through http://www.cancer.org. Accessed June 2012. 

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

Ballentine Carter, H., et. al. (2204 September 22). Report to the Nation on Prostate Cancer 2004, Chapter 1: Detection, Diagnosis, and Prognosis of Prostate Cancer CME. Medscape Today, Clinical Update [On-line CME]. Available online at http://www.medscape.com/viewprogram/3440?src=sidesearch through http://www.medscape.com.

(2005 January 1, Revised). Detailed Guide: Prostate Cancer, Can Prostate Cancer Be Found Early? American Cancer Society [On-line information]. Available online through http://www.cancer.org.

(2004 August 17, Reviewed). The Prostate-Specific Antigen (PSA) Test: Questions and Answers. National Cancer Institute, Cancer Facts [On-line information]. Available online at http://cis.nci.nih.gov/fact/5_29.htm through http://cis.nci.nih.gov.

(2004 May 26). Some Men with Low PSAs Have Prostate Cancer: Most Cancers Found Are Not Likely to Be Clinically Significant. NIH News [On-line Press Release]. Available online at http://www.nih.gov/news/pr/may2004/nci-26.htm through http://www.nih.gov.

(© 1995 – 2004). Benign Prostatic Hyperplasia. Merck Manual [On-line information]. Available online through http://www.merck.com.

(2003 March, Reviewed). Benign Prostatic Hyperplasia (BPH). Familydoctor.org [[On-line information]. Available online at http://familydoctor.org/148.xml through http://familydoctor.org.

(2003 August, Reviewed). American Urological Association. Benign Prostatic Hyperplasia (BPH), A Patient’s Guide. Available online through http://www.urologyhealth.org.

Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 772-774.

Clarke, W. and Dufour, D. R., Editors (© 2006). Contemporary Practice in Clinical Chemistry: AACC Press, Washington, DC. Pp 243, 246.

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 906-913.

(2008 November 20). What you need to know about Prostate Cancer. National Cancer Institute [On-line information]. Available online at http://www.cancer.gov/cancertopics/wyntk/prostate through http://www.cancer.gov. Accessed March 2009.

(© 2009). Detailed Guide: Prostate Cancer. American Cancer Society [On-line information]. Available online at http://www.cancer.org/docroot/CRI/CRI_2_3x.asp?rnav=cridg&dt=36 through http://www.cancer.org. Accessed March 2009.

(2009 March 19). PSA Testing: What Should Men Do? Fallout from 2 studies, pro and con, has experts in a quandary. MedlinePlus HealthDay [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/news/fullstory_81937.html through http://www.nlm.nih.gov. Accessed March 2009.

Morse Linn, M. et al (Posted 2008 January 9). Prostate-Specific Antigen Screening: Friend or Foe? Emedicine from Urol Nurs. 2007;27(6):481-489. [On-line information]. Available online at http://www.medscape.com/viewarticle/568053 through http://www.medscape.com. Accessed March 2009.

Chustecka, Z. News and Lie, D. CME (Released 2008 August 5). USPSTF Recommends Against Prostate Cancer Screening in Men 75 Years or Older. CME/CE Medscape Medical News, Online CME [On-line information]. Available online at http://www.medscape.com/viewarticle/578591 through http://www.medscape.com. Accessed March 2009.

Michael, A. et al (Posted 2009 March 6). Prostate Cancer Chemotherapy in the Era of Targeted Therapy. Medscape from Prostate Cancer Prostatic Dis. 2009;12(1):13-16. [On-line information]. Available online at http://www.medscape.com/viewarticle/589071 through http://www.medscape.com. Accessed March 2009.

Melanie Ketchandji, M. et al (Posted 2009 February 5). Cause of Death in Older Men After the Diagnosis of Prostate Cancer. Medscape from J Am Geriatr Soc. 2009;57(1):24-30. Available online at http://www.medscape.com/viewarticle/586741 through http://www.medscape.com. Accessed March 2009.

(Reviewed 2009 March 18). Prostate-Specific Antigen (PSA) Test. NCI Fact Sheet [On-line information]. Available online at http://www.cancer.gov/cancertopics/factsheet/Detection/PSA through http://www.cancer.gov. Accessed March 2009.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER and Bruns DE, eds. 4th ed. St. Louis, Missouri: Elsevier Saunders; 2006, Pg 761.

(July 30, 2009) American Cancer Society. Following PSA Levels After Treatment Meant to Cure Prostate Cancer. Available online at http://www.cancer.org/docroot/CRI/content/CRI_2_4_4X_Following_PSA_levels_36.asp?sitearea= through http://www.cancer.org. Accessed August 2009.

McDermed J. Using PSA Intelligently to Manage Prostate Cancer. Part 2 of 2. PCRI Insights. August, 2005. Vol. 8, no. 3. Available online at http://www.prostate-cancer.org/education/preclin/McDermed_Using_PSA_Intelligently2.html through http://www.prostate-cancer.org. Accessed November 2009.

Pagana K, Pagana T. Mosby's Manual of Diagnostic and Laboratory Tests. 3rd Edition, St. Louis: Mosby Elsevier; 2006 Pp.430.

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