Diagnosis

Your doctor will start by asking detailed questions about your symptoms and doing a physical exam. This initial exam is likely to include:

• Digital rectal exam. The doctor inserts a finger into the rectum to check your prostate for enlargement.
• Urine test. Analyzing a sample of your urine can help rule out an infection or other conditions that can cause similar symptoms.
• Blood test. The results can indicate kidney problems.
• Prostate-specific antigen (PSA) blood test. PSA is a substance produced in your prostate. PSA levels increase when you have an enlarged prostate. However, elevated PSA levels can also be due to recent procedures, infection, surgery or prostate cancer.

After that, your doctor might recommend additional tests to help confirm an enlarged prostate and to rule out other conditions. These tests include:

• Urinary flow test. You urinate into a receptacle attached to a machine that measures the strength and amount of your urine flow. Test results help determine over time if your condition is getting better or worse.
• Postvoid residual volume test. This test measures whether you can empty your bladder completely. The test can be done using ultrasound or by inserting a catheter into your bladder after you urinate to measure how much urine is left in your bladder.
• 24-hour voiding diary. Recording the frequency and amount of urine might be especially helpful if more than one-third of your daily urinary output occurs at night.

If your condition is more complex, your doctor may recommend:

• Transrectal ultrasound. An ultrasound probe is inserted into your rectum to measure and evaluate your prostate.
• Prostate biopsy. Transrectal ultrasound guides needles used to take tissue samples (biopsies) of the prostate. Examining the tissue can help your doctor diagnose or rule out prostate cancer.
• Urodynamic and pressure flow studies. A catheter is threaded through your urethra into your bladder. Water — or, less commonly, air — is slowly injected into your bladder. Your doctor can then measure bladder pressure and determine how well your bladder muscles are working. These studies are usually used only in men with suspected neurological problems and in men who have had a previous prostate procedure and still have symptoms.
• Cystoscopy. A lighted, flexible instrument (cystoscope) is inserted into your urethra, allowing your doctor to see inside your urethra and bladder. You will be given a local anesthetic before this test.