Blood test performed to measure prostate specific antigen (PSA), produced by the prostate gland is known as PSA test. PSA is a protein which is released by the prostate gland. Normally, very small amount of PSA is present in the bloodstream of a healthy man. The U.S. Food and Drug Administration (FDA) has approved PSA test and it is recommended that men above 50 should undergo a PSA test annually, because the test helps detect prostate cancer at an early stage. Those diagnosed with prostate cancer need to undergo the test regularly, as it helps check whether the treatment has been effective or it needs to be changed.
Different laboratories consider different PSA values as the normal values. According to some laboratories, normal value for total PSA should be less than 4.0 ng/ml (nanograms per milliliter of blood), while according to some, it should be less than 2.5 ng/ml; so that it will be possible to detect more cases of prostate cancer in early stages. An elevated level of PSA suggests higher chances of having prostate cancer. But experts argue that lowering the value of normal total PSA might lead to over-diagnosing. According to them, over treating of 'clinically insignificant' (that may never cause significant health problems) cancers may result in serious side effects and it is not necessary to treat the condition which is never going to cause any problem in future. Besides, PSA levels rise not only in case of prostate cancer but also in several other conditions.
|PSA Test Numbers||Interpretation|
|Less than 4 ng/mL||Normal|
|4 - 10 ng/mL||20 - 30 % risk of cancer|
|10 - 20 ng/mL||50 - 75 % risk of cancer|
|Above 20 ng/mL||90 % risk of cancer|
PSA Levels by Age
|PSA Levels||Normal for Men|
|Less than 2.4 ng/mL||Under the Age of 50 Years|
|3 ng/mL or Less||Under the Age of 60 Years|
|4 ng/ml or Less||In the Age Group of 60 to 69|
|5 ng/ml or Less||Aged Over 70 Years|
PSA numbers help evaluate prostate health. If prostate is completely removed, then PSA should not be found in the blood. Zero PSA is expected after the surgery.
PSA Test and DRE
Along with the PSA test, DRE (Digital Rectal Exam) test can be advised to assess prostate health. A biopsy also helps confirm the diagnosis of prostate cancer. Apart from cancer, high PSA levels are noticed in other situations like prostatitis or inflammation of the prostate gland and benign prostatic hyperplasia (BPH) or enlarged prostate. So to confirm the diagnosis, DRE is also suggested along with the PSA test. Enlarged prostate is a very common condition among elderly men. Just as over-diagnosing is not desired, missing the detection of aggressive cancers is also not desired.
Interpretation of PSA Test Results
Doctors check 'free PSA' if a man has slightly raised level of 'total PSA'. The ratio of free to total PSA helps decide whether the person is at an increased risk of having prostate cancer and whether a biopsy is essential.
According to the American Cancer Society (ACS), a total PSA level greater than 10.0 ng/ml indicates that the person is at an increased risk (more than 67% chance) of prostate cancer. PSA range '4.0 ng/ml to 10.0 ng/ml' indicates that there are about 25% chances of development of prostate cancer (according to the ACS). The range of 4 to 10 ng/ml suggests occurrence of BPH or prostatitis. Levels of PSA in elderly men can be in between 4 - 10 ng/ml. These men are said to be in the 'gray zone'. Measuring 'free PSA' is essential if you are in this zone. Men in the gray zone who have low levels of free PSA, are more likely to develop prostate cancer. High levels of free PSA in these men means the risk of cancer is comparatively less.
If a person complains about pain or difficulty while urinating, and/or frequent urination and if he is suffering from back pain, and/or pelvic pain, a PSA test might be advised. This does not mean that the person has cancer. These symptoms may also be a sign of other conditions, like infection and prostatitis. The doctor may order other tests, such as 'urine culture'. It has been noticed that conditions like infection or prostatitis can lead to a temporary rise in blood PSA. If elevated level of total PSA is noticed, you will be again asked to undergo a PSA test, after a few weeks, in order to check whether the PSA level is still elevated or it has come back to normal.
It is necessary to interpret PSA test results carefully. The amount of PSA in blood naturally increases along with aging. It is believed that American men of African descent and men with a family history of prostate cancer are at an increased risk of prostate cancer. So such men over 40 should get their PSA levels checked annually. As mentioned above, PSA numbers are assessed in various ways and the cut-off values may vary from laboratory to laboratory, so you should consult your doctor for correct interpretation.