PSA is commonly known as the Prostate-specific antigen. This particular part of your routine blood exam is quintessentially like hCG for women, except that it exclusively is for men. Unlike hCG, which is in most cases used to determine pregnancy, PSA is ultimately used to determine whether or not a man has prostate cancer.
Unlike hCG levels, a typical man without prostate cancer has already within him a certain level of PSA, usually under 4 ng/ml. This fact is important in determining whether the PSA levels are elevated enough to cause a patient to have prostate problems. Perhaps the most startling piece of information associated with PSA is the fact that once the levels reach higher than 10 ng/ml, the risk of prostate cancer increases to about 67%.
The PSA blood test, much like self-checking for lumps in the breasts or a typical prostate exam is a part of growing older. As men grow older, the fluctuations in the levels of PSA occur during the later adult cycle. Furthermore, just because the PSA level is below 4 doesn't mean that the person will never develop prostate cancer - it just significantly reduces the odds that this will happen.
Testing in general is something that needs to be done every year. As a man gets older, these tests should routinely be done in order to rule out the possibility of prostate cancer. Much like the annual prostate exam, monitoring the levels of PSA along with the prostate exam is a sure-fire way of detecting prostate cancer early if it should ever arise. The early detection of the prostate cancer is an effective tool in treatment, which leading experts agree lead to cures in more cases.
Should the blood levels indicate an alarming amount of PSA, the doctor in charge may order a biopsy of the prostate tissue. This of course is usually something that only occurs if the physician feels that there is something truly and significantly wrong and may just be using the second test to confirm the diagnosis of prostate cancer.
The exam is painless, as is usual with blood tests, and the actual test is performed only after the collection of the blood. Once again, your physician knows best, and will be able to diagnose the prostate cancer more efficiently than a number on a sheet will ever be able to do.