Tests and diagnosis

By Mayo Clinic Staff

An initial evaluation for enlarged prostate will likely include:

  • Detailed questions about your symptoms. Your doctor will want to know about other health problems you may have, what medications you're taking and whether there's a history of prostate problems in your family. Your doctor may have you complete a questionnaire such as the American Urological Association (AUA) Symptom Index for BPH.
  • Digital rectal exam. This exam can allow your doctor to check your prostate by inserting a finger into your rectum. With this simple test, your doctor can determine whether your prostate is enlarged and check for signs of prostate cancer.
  • Neurological exam. This is a brief evaluation of your mental functioning and nervous system. It can help identify causes of urinary problems other than enlarged prostate. What this exam involves will depend on your specific condition.
  • Urine test (urinalysis). Analyzing a sample of your urine in the laboratory can help rule out an infection or other conditions that can cause similar symptoms.

Your doctor may use additional tests to rule out other problems and help confirm enlarged prostate is causing your urinary symptoms. These can include:

  • Prostate-specific antigen (PSA) blood test. It's normal for your prostate gland to produce PSA, which helps liquefy semen. When you have an enlarged prostate, PSA levels increase. However, PSA levels can also be elevated due to prostate cancer, recent tests, surgery or infection (prostatitis).
  • Urinary flow test. This test measures the strength and amount of your urine flow. You urinate into a receptacle attached to a special machine. The results of this test over time help determine if your condition is getting better or worse.
  • Postvoid residual volume test. This test measures whether you can empty your bladder completely. This is often done by using an ultrasound test to measure urine left in your bladder. Or, it may be done by inserting a tube (catheter) into your bladder after you urinate.
  • Transrectal ultrasound. An ultrasound test provides measurements of your prostate and also reveals the particular anatomy of your prostate. With this procedure, an ultrasound probe about the size and shape of a large cigar is inserted into your rectum. Ultrasound waves bouncing off your prostate create an image of your prostate gland.
  • Prostate biopsy. With this procedure, a transrectal ultrasound guides needles used to take tissue samples of the prostate. Examining tissues from a biopsy under a microscope can be help diagnose or rule out prostate cancer.
  • Urodynamic studies and pressure flow studies. With these procedures, a catheter is threaded through your urethra into your bladder. Water (or less commonly air) is slowly injected into your bladder. This allows your doctor to measure bladder pressures and to determine how well your bladder muscles are working.
  • Cystoscopy. Also called urethrocystoscopy, this procedure allows your doctor to see inside your urethra and bladder. After you receive a local anesthetic, a lighted flexible telescope (cystoscope) is inserted into your urethra to look for signs of problems.
  • Intravenous pyelogram or CT urogram. These tests can help detect urinary tract stones, tumors or blockages above the bladder. First, dye is injected into a vein, and X-rays or CT scans are taken of your kidneys, bladder and the tubes that connect your kidneys to your bladder (ureters). The dye helps outline the drainage systems of the kidneys.

Other possible causes of urinary symptoms

Your doctor will use these tests to make sure there isn't something else causing your problem, or if an enlarged prostate has caused or worsened another problem. Problems that can cause urinary symptoms similar to those caused by enlarged prostate include:

  • Bladder stones
  • Bladder and urinary tract infections
  • Diabetes
  • Neurological problems
  • Inflammation of the prostate (prostatitis)
  • Prostate cancer
  • Stroke
  • Muscle and nerve (neuromuscular) disorders
  • Scarring or narrowing of the urethra

Prostate cancer is entirely different than prostate gland enlargement, even though they can cause some similar symptoms and may be detected by some of the same tests. Having an enlarged prostate doesn't reduce or increase the risk of prostate cancer. Even if you're being treated for an enlarged prostate gland, you still need to continue regular prostate exams to screen for cancer. Surgery for prostate gland enlargement may identify cancer in its early stages.

Dec. 06, 2011

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