- The PSA Test and Screening- Prostate Cancer Foundation
- What does PSA Mean?
- What is the PSA Test?
- Screening Tests for Prostate Cancer
- Prostate-specific antigen (PSA) blood test
- Factors that might affect PSA levels
- Special types of PSA tests
- Digital rectal exam (DRE)
- Prostate-Specific Antigen (PSA) Test: MedlinePlus Lab Test Information
- Prostate Specific Antigen (PSA)
- Prostate Cancer Detection: PSA Screening
- What is Prostate-Specific Antigen?
- What is the controversy surrounding PSA screening?
- When should I get a PSA test?
- How can I get a PSA test?
- Understanding Your PSA Test
- If Your PSA is High
- If Your PSA is Low
- If Your PSA is Rising Quickly
- Additional Testing
- The Prostate-Specific Antigen (PSA) Blood Test
The PSA Test and Screening- Prostate Cancer Foundation
There are two primary means of screening for prostate cancer.
Along with the digital rectal exam (or DRE), in which a physician inserts a gloved finger into the rectum to examine the prostate for irregularities, a PSA test is the leading method of screening for prostate cancer. A PSA test can help catch the disease at an early stage when treatment is thought to be more effective and potentially has fewer side effects.
What does PSA Mean?
PSA, or prostate specific antigen, is a protein produced by the prostate and found mostly in semen, with very small amounts released into the bloodstream.
When there’s a problem with the prostate—such as the development and growth of prostate cancer—more PSA is released. Sometimes, a man’s prostate releases slightly high PSA for other reasons.
Rising PSA eventually reaches a level where it can be easily detected by a blood test.
For more information on rising PSA, download or order your free copy of the Prostate Cancer Patient Guide.
What is the PSA Test?
During a PSA test, a small amount of blood is drawn from the arm, and the level of PSA, a protein produced by the prostate (not prostrate), is measured. Normal PSA ranges can vary according to factors unique to each man, so the PSA test is just a part of the process of screening for prostate cancer.
Doctors look at the overall PSA numbers, as well as the rate at which it rises over time and repeated tests (velocity). As the PSA number goes up, the chance that cancer is present increases.
Depending on their age, men whose levels go above 3 or 4 are often recommended to undergo a biopsy; however, this PSA level does not mean that prostate cancer is definitely there, and some cancers be present even when PSA levels are lower.
In general, older men’s normal PSA levels run a little higher than those of younger men.
Normal levels tend to vary a little between different ethnic groups, but in general, see this PSA chart:
|If you are in your …||Your normal PSA range should be …|
What is a high PSA level and what is a normal PSA level vary by demographic factors. Your doctor will evaluate your test results, factor in your age, ethnicity, and any other relevant factors, and let you know whether your results suggest more testing.
Remember that assessment of PSA must also take into account:
- Prostate size: A man with a larger-than-usual prostate may have a higher-than-usual normal PSA level.
- Prostatitis: Prostatitis is a painful condition, often caused by bacterial infection in which the prostate is inflamed, swollen, and tender. Prostatitis can cause high PSA.
- Benign prostatic hyperplasia (BPH): BPH is an enlarged prostate. It may make urination or ejaculation difficult, and along with the swelling, may cause a spike in PSA levels.
- Urinary tract infection or irritation: An infection of the urinary tract, as well as irritation caused by medical procedures involving the urethra or bladder, may irritate the prostate and cause it to produce more PSA.
- Prostate stimulation: Sexual activity (or even a DRE) can cause temporarily high PSA.
- Medications: Some medications, such as finasteride (Proscar or Propecia) or dutasteride (Avodart), can cause low PSA numbers.
Each time you see your doctor for a checkup, have a conversation about prostate health and prostate cancer screening. PSA levels can be influenced by many different factors—it’s just one piece of the puzzle.
Screening Tests for Prostate Cancer
Screening is testing to find cancer in people before they have symptoms. It’s not clear, however, if the benefits of prostate cancer screening outweigh the risks for most men. Still, after discussing the pros and cons of screening with their doctors, some men might reasonably choose to be screened.
The screening tests discussed here are used to look for possible signs of prostate cancer. But these tests can’t tell for sure if you have cancer. If the result of one of these tests is abnormal, you will probably need a prostate biopsy (discussed below) to know for sure if you have cancer.
Prostate-specific antigen (PSA) blood test
Prostate-specific antigen (PSA) is a protein made by cells in the prostate gland (both normal cells and cancer cells). PSA is mostly found in semen, but a small amount is also found in blood.
The PSA level in blood is measured in units called nanograms per milliliter (ng/mL).
The chance of having prostate cancer goes up as the PSA level goes up, but there is no set cutoff point that can tell for sure if a man does or doesn’t have prostate cancer.
Many doctors use a PSA cutoff point of 4 ng/mL or higher when deciding if a man might need further testing, while others might recommend it starting at a lower level, such as 2.5 or 3.
- Most men without prostate cancer have PSA levels under 4 ng/mL of blood. When prostate cancer develops, the PSA level often goes above 4. Still, a level below 4 is not a guarantee that a man doesn’t have cancer. About 15% of men with a PSA below 4 will have prostate cancer if a biopsy is done.
- Men with a PSA level between 4 and 10 (often called the “borderline range”) have about a 1 in 4 chance of having prostate cancer.
- If the PSA is more than 10, the chance of having prostate cancer is over 50%.
If your PSA level is high, you might need further tests to look for prostate cancer (see ‘If screening tests results aren’t normal’, below).
Factors that might affect PSA levels
One reason it’s hard to use a set cutoff point with the PSA test when looking for prostate cancer is that a number of factors other than cancer can also affect PSA levels.
Factors that might raise PSA levels include:
- An enlarged prostate: Conditions such as benign prostatic hyperplasia (BPH), a non-cancerous enlargement of the prostate that affects many men as they grow older, can raise PSA levels.
- Older age: PSA levels normally go up slowly as you get older, even if you have no prostate abnormality.
- Prostatitis: This is an infection or inflammation of the prostate gland, which can raise PSA levels.
- Ejaculation: Thiscan make the PSA go up for a short time. This is why some doctors suggest that men abstain from ejaculation for a day or two before testing.
- Riding a bicycle: Some studies have suggested that cycling may raise PSA levels for a short time (possibly because the seat puts pressure on the prostate), although not all studies have found this.
- Certain urologic procedures: Some procedures done in a doctor’s office that affect the prostate, such as a prostate biopsy or cystoscopy, can raise PSA levels for a short time. Some studies have suggested that a digital rectal exam (DRE) might raise PSA levels slightly, although other studies have not found this. Still, if both a PSA test and a DRE are being done during a doctor visit, some doctors advise having the blood drawn for the PSA before having the DRE, just in case.
- Certain medicines: Taking male hormones testosterone (or other medicines that raise testosterone levels) may cause a rise in PSA.
Some things might lower PSA levels (even if a man has prostate cancer):
- 5-alpha reductase inhibitors: Certain drugs used to treat BPH or urinary symptoms, such as finasteride (Proscar or Propecia) or dutasteride (Avodart), can lower PSA levels. These drugs can also affect prostate cancer risk (discussed in Can Prostate Cancer Be Prevented?). Tell your doctor if you are taking one of these medicines. Because they can lower PSA levels, the doctor might need to adjust for this.
- Herbal mixtures: Some mixtures that are sold as dietary supplements might mask a high PSA level. This is why it’s important to let your doctor know if you are taking any type of supplement, even ones that are not necessarily meant for prostate health. Saw palmetto (an herb used by some men to treat BPH) does not seem to affect PSA.
- Certain other medicines: Some research has suggested that long-term use of certain medicines, such as aspirin, statins (cholesterol-lowering drugs), and thiazide diuretics (such as hydrochlorothiazide) might lower PSA levels. More research is needed to confirm these findings. If you take any of the medicines regularly, talk to your doctor before you stop taking it for any reason.
For men who might be screened for prostate cancer, it’s not always clear if lowering the PSA is helpful. In some cases the factor that lowers the PSA may also lower a man’s risk of prostate cancer.
But in other cases, it might lower the PSA level without affecting a man’s risk of cancer. This could actually be harmful, if it were to lower the PSA from an abnormal level to a normal one, as it might result in not detecting a cancer.
This is why it’s important to talk to your doctor about anything that might affect your PSA level.
Special types of PSA tests
If you decide to get a PSA screening test and the result isn’t normal, some doctors might consider using different types of PSA tests to help decide if you need a prostate biopsy, although not all doctors agree on how to use these tests. If your PSA test result isn’t normal, ask your doctor to discuss your cancer risk and your need for further tests.
Percent-free PSA: PSA occurs in 2 major forms in the blood. One form is attached to blood proteins, while the other circulates free (unattached). The percent-free PSA (%fPSA) is the ratio of how much PSA circulates free compared to the total PSA level. The percentage of free PSA is lower in men who have prostate cancer than in men who do not.
If your PSA test result is in the borderline range (between 4 and 10), the percent-free PSA might be used to help decide if you should have a prostate biopsy. A lower percent-free PSA means that your chance of having prostate cancer is higher and you should probably have a biopsy.
Many doctors recommend a prostate biopsy for men whose percent-free PSA is 10% or less, and advise that men consider a biopsy if it is between 10% and 25%.
Using these cutoffs detects most cancers and helps some men avoid unnecessary biopsies.
This test is widely used, but not all doctors agree that 25% is the best cutoff point to decide on a biopsy, and the cutoff may change depending on the overall PSA level.
Complexed PSA: This test directly measures the amount of PSA that is attached to other proteins (the portion of PSA that is not “free”). This test could be done instead of checking the total and free PSA, and it could give the same amount of information, but it is not widely used.
Tests that combine different types of PSA: Some newer tests combine the results of different types of PSA to get an overall score that reflects the chance a man has prostate cancer (particularly cancer that might need treatment).These tests include:
- The Prostate Health Index (PHI), which combines the results of total PSA, free PSA, and proPSA
- The 4Kscore test, which combines the results of total PSA, free PSA, intact PSA, and human kallikrein 2 (hK2), along with some other factors
These tests might be useful in men with a slightly elevated PSA, to help determine if they should have a prostate biopsy. These tests might also be used to help determine if a man who has already had a prostate biopsy that didn’t find cancer should have another biopsy.
PSA velocity: The PSA velocity is not a separate test. It is a measure of how fast the PSA rises over time. Normally, PSA levels go up slowly with age.
Some research has found that these levels go up faster if a man has cancer, but studies have not shown that the PSA velocity is more helpful than the PSA level itself in finding prostate cancer.
For this reason, the ACS guidelines do not recommend using the PSA velocity as part of screening for prostate cancer.
PSA density: PSA levels are higher in men with larger prostate glands. The PSA density (PSAD) is sometimes used for men with large prostate glands to try to adjust for this.
The doctor measures the volume (size) of the prostate gland with transrectal ultrasound (discussed in Tests to Diagnose and Stage Prostate Cancer) and divides the PSA number by the prostate volume. A higher PSA density indicates a greater lihood of cancer.
PSA density has not been shown to be as useful as the percent-free PSA test.
Age-specific PSA ranges: PSA levels are normally higher in older men than in younger men, even when there is no cancer. A PSA result within the borderline range might be worrisome in a 50-year-old man but cause less concern in an 80-year-old man. For this reason, some doctors have suggested comparing PSA results with results from other men of the same age.
But the usefulness of age-specific PSA ranges is not well proven, so most doctors and professional organizations (as well as the makers of the PSA tests) do not recommend their use at this time.
Digital rectal exam (DRE)
For a digital rectal exam (DRE), the doctor inserts a gloved, lubricated finger into the rectum to feel for any bumps or hard areas on the prostate that might be cancer.
As shown in the picture below, the prostate is just in front of the rectum. Prostate cancers often begin in the back part of the gland, and can sometimes be felt during a rectal exam.
This exam can be uncomfortable (especially for men who have hemorrhoids), but it usually isn’t painful and only takes a short time.
Prostate-Specific Antigen (PSA) Test: MedlinePlus Lab Test Information
URL of this page: https://medlineplus.gov/lab-tests/prostate-specific-antigen-psa-test/
A prostate-specific antigen (PSA) test measures the level of PSA in your blood. The prostate is a small gland that is part of a man's reproductive system. It is located below the bladder and makes a fluid that is part of semen.
PSA is a substance made by the prostate. Men normally have low PSA levels in their blood. A high PSA level may be a sign of prostate cancer, the most common non-skin cancer affecting American men.
But high PSA levels can also mean noncancerous prostate conditions, such as infection or benign prostatic hyperplasia, a noncancerous enlargement of the prostate.
Other names: total PSA, free PSA
A PSA test is used to screen for prostate cancer. Screening is a test that looks for a disease, such as cancer, in its early stages, when it's most treatable.
Leading health organizations, such as the American Cancer Society and the Centers for Disease Control and Prevention (CDC), disagree on recommendations for using the PSA test for cancer screening.
Reasons for disagreement include:
- Most types of prostate cancer grow very slowly. It can take decades before any symptoms show up.
- Treatment of slow-growing prostate cancer is often unnecessary. Many men with the disease live long, healthy lives without ever knowing they had cancer.
- Treatment can cause major side effects, including erectile dysfunction and urinary incontinence.
- Fast-growing prostate cancer is less common, but more serious and often life-threatening. Age, family history, and other factors can put you at higher risk. But the PSA test alone can't tell the difference between slow- and fast-growing prostate cancer.
To find out if PSA testing is right for you, talk to your health care provider.
You may get a PSA test if you have certain risk factors for prostate cancer. These include:
- A father or brother with prostate cancer
- Being African-American. Prostate cancer is more common in African-American men. The reason for this is unknown.
- Your age. Prostate cancer is more common in men over the age of 50.
You may also get a PSA test if:
- You have symptoms such as painful or frequent urination, and pelvic and/or back pain.
- You've already been diagnosed with prostate cancer. The PSA test can help monitor the effects of your treatment.
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
You will need to avoid having sex or masturbating for 24 hours before your PSA test, as releasing semen can raise your PSA levels.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
High PSA levels can mean cancer or a noncancerous condition such as a prostate infection, which can be treated with antibiotics. If your PSA levels are higher than normal, your health care provider will probably order more tests, including:
- A rectal exam. For this test, your health care provider will insert a gloved finger into your rectum to feel your prostate.
- A biopsy. This is a minor surgical procedure, where a provider will take a small sample of prostate cells for testing.
If you have questions about your results, talk to your health care provider.
Researchers are looking into ways to improve the PSA test. The goal is to have a test that does a better job of telling the difference between non-serious, slow-growing prostate cancers and cancers that are fast growing and potentially life-threatening.
Prostate Specific Antigen (PSA)
Sources Used in Current Review
(April 14, 2016) American Cancer Society. What tests can detect prostate cancer early? Available online at https://www.cancer.org/cancer/prostate-cancer/early-detection/tests.html. Accessed September 2019.
(August 1, 2019) American Cancer Society. Key statistics for prostate cancer. Available online at https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html. Accessed September 2019.
(May 2018) U.S. Preventive Services Task Force. Final recommendation statement: Prostate cancer: Screening. Available online at https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/prostate-cancer-screening1. Accessed September 2019.
Sokoll, L.J., et al. (February, 2016) Do ultrasensitive prostate specific antigen measurements have a role in predicting long-term biochemical recurrence-free survival in men after radical prostatectomy? J Urol. Available online at https://doi.org/10.1016/j.juro.2015.08.080. Accessed September 2019.
Eastham, J.A., et al. (May 28, 2003). Variation of serum prostate-specific antigen levels: An evaluation of year-to-year fluctuations. JAMA. Available online at http://dx.doi.org/10.1001/jama.289.20.2695. Accessed September 2019.
Jansen, F.H., et al. (February 15, 2010). Prostate-specific antigen (PSA) isoform p2PSA in combination with total PSA and free PSA improves diagnostic accuracy in prostate cancer detection. Eur. Urol. Available online at https://doi.org/10.1016/j.eururo.2010.02.003. Accessed September 2019.
(July 5, 2017) Mayo Clinic. Mayo Medical Laboratories, Test ID: PHI11, prostate health Index (phi), serum. Available online at https://www.mayomedicallaboratories.com/test-catalog/Overview/113000. Accessed September 2019.
White, J., et al. (November 20, 2017) Clinical utility of the Prostate Health Index (phi) for biopsy decision management in a large group urology practice setting. Prostate Cancer Prostatic Dis. Available online at https://doi.org/10.1038/s41391-017-0008-7. Accessed September 2019.
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.
(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.
(2004 May 26). Some Men with Low PSAs Have Prostate Cancer: Most Cancers Found Are Not ly to Be Clinically Significant. NIH News [On-line Press Release]. Available online at http://www.nih.gov/news/pr/may2004/nci-26.htm.
(© 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.
(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. 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. 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. 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. 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. 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. 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. 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. 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=. 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. Accessed November 2009.
Pagana K, Pagana T. Mosby's Manual of Diagnostic and Laboratory Tests. 3rd Edition, St. Louis: Mosby Elsevier; 2006 Pp.430.
(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. 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. 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. 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. 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/. 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. 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. 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. Accessed June 2012.
Prostate Cancer Detection: PSA Screening
The most common screening tool for prostate cancer is the prostate-specific antigen (PSA) test. This is a simple blood test that measures the presence of PSA circulating in your bloodstream. This test is usually the first step in any prostate cancer diagnosis. However, the PSA screening by itself cannot tell you if cancer is present.
The PSA test is also used to track the effects of prostate cancer treatment such as surgery, radiation, hormone therapy and chemotherapy. When a man has treatment for prostate cancer, his PSA level will drop significantly. Regular screening with PSA is one of the tools the physician will use to measure if the cancer has returned.
When PSA levels rise to a certain threshold after prostate cancer treatment, this is known as biochemical recurrence. This means that some cancer cells have survived and are producing PSA. If this happens, the doctor will order additional tests and make recommendations for additional treatment.
What is Prostate-Specific Antigen?
PSA is a protein produced by prostate cells, which keeps semen in liquid form so that sperm can swim. A simple blood test can measure how much PSA is present in a man’s bloodstream. When a man has prostate cancer, his PSA level increases, which is why the PSA test is used as a screening tool.
However, the levels of PSA can rise due to a number of reasons, including cancer. When PSA is elevated it is a warning sign that you should follow up on with your doctor.
What is the controversy surrounding PSA screening?
In recent years, there has been some controversy surrounding the PSA test. In 2012, the U.S. Preventive Services Task Force (USPSTF) assigned the PSA test a “D” rating.
This meant that the USPSTF concluded the harms that resulted from PSA testing, such as unnecessary biopsies and negative treatment side effects, outweighed the benefits of finding and managing the disease early.
This recommendation did not include exceptions for men at increased risk of developing the disease, such as African American men, those with a family history of the disease, and those with BRCA gene mutations.
The USPSTF recommendation is important as it guides primary care physicians in preventive care and can impact insurance coverage and reimbursement for screening. Prior to its “D” rating, the PSA test had an “I” rating, meaning the USPSTF concluded there was insufficient evidence to assess the pros and cons of testing.
In May 2018, the USPSTF updated their recommendation on PSA screening.
In response to new research demonstrating the benefits of PSA screening (such as the European Randomized Study of Screening for Prostate Cancer), an increase in the number of men choosing active surveillance, and advocacy efforts, the USPSTF released a draft recommendation in April 2017 that assigns the PSA test a “C” rating for men ages 55to 69 (the test still has a “D” rating for men ages 70+). This rating has now been certified official by the task force.
This means that the USPSTF recognizes a small potential benefit of PSA testing and recommends that men make individual decisions about whether or not to get tested after discussing the risks and benefits with their doctors. the 2012 recommendation, this update does not include specific language for men at increased risk.
The National Comprehensive Cancer Network® (NCCN®) and ZERO – The End of Prostate Cancer strongly recommend that men should be fully educated about prostate cancer, should know their options for early detection, and should have access to the tests we have available now.
Researchers, with support from organizations ZERO, are working every day to improve prostate cancer screening, but for now, we must use the tools we have. A PSA test score is an important part of making a decision on how best to determine a prostate cancer diagnosis and/or treatment pathway.
Visit our advocacy site to learn about ZERO’s advocacy efforts in early detection and access to PSA screening.
This 2016 article by Dr. Stacy Loeb provides a thorough overview of the evidence for and against the PSA test, and how we can interpret this evidence with nuance in order to prevent suffering and death.
When should I get a PSA test?
The guidelines below are adapted from the NCCN Clinical Practice Guidelines In Oncology (NCCN Guidelines®) for Prostate Cancer Early Detection. Please use these guidelines to have a discussion with your physician about your personal risk and make a plan for screening.
- If you are between ages 45 and 75:
- Discuss the risks and benefits of prostate cancer screening with your doctor, have a baseline PSA, and consider a baseline DRE
- If your PSA is below 1 ng/mL and your DRE is normal, repeat testing every 2-4 years
- If your PSA is between 1 and 3 ng/mL and your DRE is normal, repeat testing every 1-2 years
- If your PSA is greater than 3 ng/ML or your DRE is very suspicious, your doctor may suggest additional testing or a biopsy
- If you are over 75:
- Decide together with your doctor if PSA/DRE testing is right for you
- If you continue testing and your psA is less than 3 ng/mL and your DRE is normal, repeat testing every 1-4 years
- If your PSA is greater than 3 ng/ML or your DRE is very suspicious, your doctor may suggest additional testing or a biopsy
Click here to create a free NCCN account and view the full NCCN Guidelines® for Prostate Cancer Early Detection.
How can I get a PSA test?
Talk to your general practitioner or urologist about receiving a PSA test in their office. If you do not have insurance or if your insurance does not cover the PSA screening, consult our national free testing map or look into our free testing partners.
- National Free Testing Map
- Community Testing Partners
Understanding Your PSA Test
In general, a PSA level that is above 4.0 ng/mL is considered suspicious. However, there are many other factors to consider before taking further action. The following are some general PSA level guidelines:
- 0 to 2.5 ng/mL is considered safe
- 2.6 to 4 ng/mL is safe in most men but talk with your doctor about other risk factors
- 4.0 to 10.0 ng/mL is suspicious and might suggest the possibility of prostate cancer. It is associated with a 25% chance of having prostate cancer.
- 10.0 ng/mL and above is dangerous and should be discussed with your doctor immediately. It is associated with a 50% chance of having prostate cancer.
However, PSA levels can easily rise with greater age. You and your physician should consult age-specific normal PSA ranges.
If Your PSA is High
You and your doctor can explore several options if your PSA is high. One option is to have a second PSA screening; recent research has shown that a second screening can improve the accuracy of an abnormal result1. A digital rectal exam (DRE) and a biopsy can also confirm the presence or absence of prostate cancer. However, there are several other reasons why a PSA result might be high:
- Advanced age
- Recent biopsy
- Injury to pelvic region or prostate
- Riding a bicycle
- Sex (within the past 24 hours)
- Supplements that effect testosterone
- Urinary tract infection
If you have an elevated PSA, talk with your doctor about your activities and your health.
If Your PSA is Low
In general, a low PSA is a good result. However, there are several reasons a PSA screening level may be artificially low including taking statins to lower cholesterol, anti-inflammatory drugs and obesity (body fat decreases the amount of PSA circulating in the blood stream). Be sure to discuss these with your doctor.
If Your PSA is Rising Quickly
The rate in yearly increase in the PSA level is known as the PSA velocity. This is one measure of prostate cancer risk, since PSA levels can rise rapidly in men who have prostate cancer. This can be especially useful to find prostate cancer in early stages before the cancer has left the capsule of the prostate.
Research shows that an increase of .75 ng/mL a year is an early indicator of prostate cancer if a man has a total PSA result between 4.0 and 10.0 ng/mL.2 Further, an increase of 2.0 ng/mL over a year period predicts a higher lihood of death due to aggressive prostate cancer.3
Research is also showing PSA velocity may be able to predict survivability from prostate cancer as men with a PSA increase of .35 ng/ML or less over a year have a 92 percent survival rate compared to PSA increases of more than .35 ng/mL over a year have a 54 percent survival rate.4
The Prostate Health Index was recently approved for the detection of prostate cancer. The PHI is a simple blood test that combines three tests in one. Research has shown that the test is better at detecting prostate cancer than the traditional PSA screening.5 The test also predicts the lihood of progression during active surveillance.
Because this test is very new, it is possible your physician has not heard of it yet. If you are interested in the test, talk with your doctor and discuss your risk, the test, and how to use the information from the test.
While none of these tests are conclusive on their own, when performed in addition to a PSA test, DRE (Digital Rectal Exam), and a biopsy, they can provide each patient with more information about their specific cancer and can aid in both the diagnosis and decision on treatment. Read more on this and further additional testing.
The Prostate-Specific Antigen (PSA) Blood Test
Prostate-specific antigen (PSA) is something made by the prostate gland. High PSA levels may be a sign of prostate cancer, a noncancerous condition such as prostatitis, or an enlarged prostate gland.
There’s no such thing as a normal PSA for any man at any given age, but most men with prostate cancer have a higher than normal level. In general:
- Safe: 0 to 2.5 ng/mL
- Safe for most: 2.6 to 4 ng/mL. Talk with your doctor about other risk factors
- Suspicious: 4 to 10 ng/mL. There’s a 25% chance you have prostate cancer.
- Dangerous: 10 ng/mL and above. Talk to your doctor right away. There’s a 50% chance you have prostate cancer.
The test involves taking blood, usually from your arm. The doctor will send the sample to a lab. Results most often come back within several days.
The first thing to do is talk to your doctor about the pros and cons of prostate cancer screening before you decide whether to be tested. Don’t get tested until you have that talk. Opinions differ about when you should do that.
The American Cancer Society says to get tested at age:
- 40 or 45 if you’re at high risk
- 50 if you’re at average risk
The American Urological Association suggests:
- Under 40: No screening
- 40 to 54: No screening if you’re at average risk. If you’re at a high risk, you and your doctor can decide.
- 55 to 69: Screening if your doctor suggests
- Over 70 or less than a 10-15 year life expectancy: No screening
The U.S. Preventive Services Task Force says:
- 55 to 69: Men with prostate cancer risks may need testing.
If your doctor thinks you might have prostate cancer either a PSA level or a rectal exam, a biopsy is the next step. This is a test where the doctor takes a small amount of tissue from your prostate and sends it to a lab for tests. It’s the only way to be sure you have cancer.
High PSA levels could be a sign of prostate cancer or a different condition prostatitis or an enlarged prostate.
Other things can affect your PSA level:
If your PSA level is high, your doctor may suggest that you get a prostate biopsy to test for cancer.
Newer PSA tests may help the doctor decide if you need a biopsy. But know that doctors don’t always agree on how to use or understand the results of these tests.
- Percent-free PSA. PSA takes two major forms in the blood. One is attached to blood proteins. The other moves around freely. The percent-free PSA test shows how much PSA moves freely compared to the total PSA level. The amount of free PSA is lower in men with prostate cancer. If your PSA results are in the borderline range (4 to 10), a low percent-free PSA (less than 10%) means there’s about a 50% chance you have prostate cancer. You should probably have a biopsy. Some doctors suggest biopsies for men whose percent-free PSA is 20 or less.
- PSA velocity. The PSA velocity isn’t a separate test. Instead, it’s a measure of the change in your PSA levels over time. Even when the total PSA value isn't higher than 4, a high PSA velocity (a rise of more than 0.75 ng/mL in 1 year) means you might have cancer and should consider a biopsy.
- Urine PCA3 test. This urine test looks for a mix of genes that shows up in 50% of PSA-tested men with prostate cancer. It's another tool to decide if you need a biopsy.
There are reasons doctors don’t agree on whether you need this test:
- Finding prostate cancer early doesn’t always protect you. The PSA test often finds small, slow-growing tumors that aren’t life-threatening. Treating them anyway, whether it’s with surgery or radiation, can expose you to harmful side effects and complications. Also, finding cancer early may not help if you have an aggressive tumor or if it spread to distant body parts before you found it.
- The results aren’t always accurate. If you have a high level but you don’t have cancer, the test results can create a lot of worry and lead to medical procedures you don’t need. A negative result if you really do have cancer can prevent you from getting treatment you do need.
Although the PSA test is used mainly to check for prostate cancer, it can also help your doctor:
- Choose a treatment. Along with an exam and tumor stage, the PSA test can help determine how advanced a prostate cancer is. This may affect treatment options.
- Check treatment success. After surgery or radiation, the doctor can watch your PSA level to see if the treatment worked. PSA levels normally fall if all of the cancer cells were removed or destroyed. A rising PSA level can mean that prostate cancer cells are present and your cancer has returned.
If you choose a watchful waiting approach to treatment, your PSA level can tell your doctor if the disease is progressing. If so, you’ll need to think about active treatment.
During hormone therapy, the PSA level can show how well the treatment is working and when it’s time to try another treatment.
New England Journal Of Medicine.
American Urological Association.
National Cancer Institute.
American Cancer Society.
News release, U.S. Preventive Services Task Force.
Cancer.net: “Prostate Cancer: Introduction.”
Zero – The End of Prostate Cancer: “PSA Screening.”
Cancer.gov: “Prostate-Specific Antigen (PSA) Test.”
© 2019 WebMD, LLC. All rights reserved. Prostate Ultrasound and Biopsy