Prostate Problem Guide
Understanding PSA numbers
In many cases where a doctor suspects that a patient may be suffering from BPH (a benign swelling or enlargement of the prostate) a PSA prostate test will be ordered. But, just what is a PSA test?
PSA stands for prostate specific antigen which is a protein produced principally by cells within the prostate. The main role of the prostate is to produce fluid which makes up part of a man's semen and the majority of the PSA produced finds its way into this fluid. A small amount however is also released into the blood where it can be found floating freely within the blood (free PSA) or bound together with other proteins (complexed PSA, or cPSA).
The PSA test is thus a blood test to assess the level of PSA and can measure the total level of total PSA, the level of free PSA and the level of complexed PSA. When a PSA test is ordered it will normally be a total PSA test and a free PSA test or cPSA test will usually be ordered individually where the doctor considers this to be necessary.
(This said it is becoming increasingly common for doctors these days to order both free & total PSA tests.)
The PSA test is just one of a series of steps that a doctor will go through in order to make a diagnosis and the first and most important thing to remember is that the PSA test on its own is not used to diagnose either BPH or indeed prostate cancer. Its principal purpose is to indicate whether BPH or prostate cancer are likely so that further tests can be carried out if required.
PSA levels will vary from one individual to another and can also rise and fall with various forms of activity and in reaction to certain infections and medication. It is rare therefore that a doctor will rely on individual PSA test results and will often order several tests spread several weeks apart, before drawing any conclusions from the PSA results.
Normally PSA is present in the blood at a concentration of about 4 nanograms per milliliter, however, PSA level ranges between 4 and 10 nanograms per milliliter indicate the possible presence of prostate cancer and are a fairly good indication of the presence of BPH. If PSA numbers rise above 10 nanograms per milliliter then the doctor will normally wish to carry out further tests to determine whether or not prostate cancer is present.
The main problem with the PSA test is seen when the results fall into the gray area between 4 and 10 nanograms per milliliter and it is here that a free PSA may be ordered. A low level of free PSA indicates the presence of a higher risk of prostate cancer, while a higher level of free PSA suggests a lower risk that the rise in total PSA is being caused by prostate cancer.
A cPSA test can also be used to give the doctor further information with cPSA levels increasing in the presence of prostate cancer.
One main use of PSA testing is seen in the field of prostate screening. Here PSA testing is carried out over a number of months (or years) and changes in PSA levels are monitored. In general terms, a rising pattern of PSA levels may be indicative of the presence of prostate cancer and the rate of increase will also give an indication of just how aggressive the cancer may be.
Finally, PSA testing is used following prostate cancer treatment to assess the effect of treatment.