To diagnose prostate enlargement, your doctor will likely begin by asking you what your symptoms are, when they developed and how often they occur. Your doctor will also want to know about other health problems, medications you're taking and whether there's a history of prostate problems in your family. Over-the-counter (OTC) drugs, such as aspirin, decongestants and antacids, are considered medications, so tell your doctor about those too. The history of when you start and stop medications is also important for your doctor to know about.

In addition, your checkup may include:

• Digital rectal exam. To perform this exam, your doctor puts on an examination glove, applies a lubricant to one finger, and then gently inserts the lubricated finger into your rectum. Because the prostate gland is located adjacent to the rectum, your doctor can feel the back wall of the gland. This allows your doctor to determine whether your prostate is enlarged and to help rule out prostate cancer.

• Urine test. Having a sample of your urine analyzed in the laboratory can help your doctor rule out an infection or other conditions that can produce symptoms similar to those of prostate enlargement, such as prostatitis, cystitis and kidney disease.

• Prostate-specific antigen (PSA) blood test. Prostate-specific antigen is naturally produced in your prostate gland to help liquefy semen. A small amount circulates in your blood. Higher-than-normal levels in your blood can indicate BPH, prostate cancer or prostatitis.

If the results of these tests suggest prostate enlargement, your doctor may want to perform additional exams. The following can help confirm the diagnosis of prostate enlargement and determine its severity:

• Urinary flow test. This test measures the strength and amount of your urine flow. By charting the results of this test, your doctor can determine if your urinary flow patterns change over time and at what rate. Keep in mind that your peak flow rate normally decreases as you age. Restricted urine flow can also be a sign of other problems, such as a weakened bladder muscle.

• Post-void residual volume test. This test measures whether you can empty your bladder. The test is done one of two ways: by inserting a thin, soft tube (catheter) into your urethra and up into your bladder or by using ultrasound imaging to see inside your bladder. The ultrasound method is more common and less uncomfortable, but often less accurate. Because the results of this test can vary, you may need to have it done more than once to get an accurate reading.

• Ultrasound. Imaging through ultrasound is used to estimate the size of your prostate gland. In addition, it can help detect problems such as an obstruction of your kidney, stones in your kidneys or prostate, or a tumor in the prostate.

• Urodynamic studies. If your doctor suspects that your symptoms may be related to a bladder problem rather than prostate enlargement, he or she may recommend a series of tests to measure bladder pressure and function. These tests are done by threading a small catheter through the urethra and into your bladder. Water is gently injected into your bladder to measure internal bladder pressure and to determine how effectively your bladder contracts. Bladder pressure is measured during bladder filling and urination.

• Cystoscopy. This procedure involves the use of a thin tube containing a lens with a light system (cystoscope) that's gently inserted into the urethra under local anesthesia. It allows your doctor to see inside the urethra and bladder. The procedure can detect problems including enlargement of the prostate, compression of the urethra due to enlarged prostate, obstruction of the urethra or bladder neck, an anatomical abnormality, and the development of stones in your bladder. These disorders may cause your bladder to weaken.

•  Intravenous pyelogram. An intravenous pyelogram is an X-ray image of the urinary tract used to help detect an obstruction or abnormality. Dye is injected into a vein, and an X-ray is taken of your kidneys, bladder and tubes that attach your kidneys to your bladder (ureters). The dye makes it possible to identify urinary stones, tumors or a blockage above your bladder.

If your signs and symptoms are mild and don't bother you, your doctor may suggest watchful waiting as an appropriate response to an enlarged prostate. Your doctor will periodically evaluate your condition to see if it improves, stays the same or worsens.

The risk you take in following this approach is that your condition could worsen over time and other problems could develop, such as infection, bleeding and kidney damage. However, these complications are uncommon.

Prostate enlargement becomes a serious health threat only if it interferes with your ability to empty your bladder. A bladder that's continuously full can interfere with your sleep, cause recurrent bladder infection or result in kidney damage. If you're unable to pass urine at all, seek immediate medical attention.

Treatments for prostate enlargement don't reduce or increase the risk of prostate cancer. Even if you're being treated for prostate enlargement, you still need to continue regular prostate exams to screen for cancer. Surgical treatment for prostate enlargement can identify cancer in its early stages.