(Prostate Specific Antigen)

           PSA is a substance that is put out by special gland cells in the prostate. This chemical is very specific to the prostate in humans and there is no other tissue in the body that produces PSA.  PSA determinations are very reliable so day after day and from lab to lab the variations are minimal.  However the lower limits of normal can be variable. A PSA blood test measures how much prostate tissue is in the body. It may be evaluated in four conditions:
  1. An enlarged prostate has more tissue in it so will produce more PSA.
  2. Prostatitis is inflammation in the prostate.  This may elevate the PSA.  However, after the prostatitis subsides the PSA usually returns to normal.
  3. Infarction in the prostate is where part of the prostate may be severely damaged because of an inflammation or lack of blood supply.  This may drive the PSA up.  Infarctions are very rare and are very hard to diagnose.
  4. Cancer of the prostate may cause the PSA to go up.  The more cancer there is in the body the higher the PSA.  The normal value of PSA is 0 - 4. Anything between 4 and 10 may be suspicious of cancer and will require the patient to have an ultrasound and biopsies. The higher the PSA is above 10 the more chance of cancer in the prostate. Sometimes the cancer may spread outside the prostate and the PSA will go even higher, reaching PSA values in the thousands of units. It is our recommendation that men above 40 should have a PSA done yearly. Especially if there is any history of cancer of the prostate.