Diagnosis Your doctor many identify an enlarged prostate as part of a regular physical exam or you may first notice the symptoms yourself then inform your doctor. The most common tests for diagnosing an enlarged prostate include: Digital rectal examination (DRE): This examination allows your doctor to feel the prostate gland and determine its general size and condition. Urine flow study to measure how quickly the urine is flowing. A reduced flow can suggest bladder outlet obstruction or decreased bladder contractility. Urine pressure study to measure the pressure in the bladder as you urinate. Urinalysis to check for blood or infection. Urine culture to look for infection. Prostate-Specific Antigen (PSA) blood test to rule out prostate cancer. Cystoscopy – during this procedure, your doctor inserts a small tube (called a cystoscope) through the opening of the urethra in the penis. The cystoscope is fitted with a small camera that allows your doctor to determine the size of the prostate gland and identify any blockage. This is important in deciding if surgery is warranted.