Enlarged Prostate Diagnosis and Testing

July 1, 2024

This page was reviewed under our medical and editorial policy by Wesley Yip, M.D., assistant professor, Division of Urology and Urologic Oncology, Department of Surgery, City of Hope^® Cancer Center Duarte

An enlarged prostate may be due to benign prostatic hyperplasia (BPH), and diagnosis of the condition involves a variety of examinations, tests and assessment of the patient’s symptoms. It begins with a physical exam to check for BPH symptoms. The physical exam also typically includes those listed below.

Digital rectal exam (DRE): Also called a rectal exam, this assessment helps a doctor understand different physical characteristics of a man’s prostate, such as its size, shape and how smooth or hard it is. This helps them determine whether additional tests are necessary. During a DRE, the doctor will ask the patient to undress from the waist down and bend over while standing or to lie on his side on the exam table with his knees drawn up to the chest. The doctor then places a lubricated gloved finger into the rectum to feel the prostate and manually evaluate the region.

Urine test: This test involves collecting urine in a small cup and testing for infection. Prior to any surgery, the care team will test the patient’s urine to look for signs of infection. If an infection is discovered, it will be treated before the operation.

Blood tests: These tests help measure how the kidneys are functioning. They include a BUN (blood urea nitrogen) test to measure the blood levels of urea, a waste product filtered out by the kidneys. A second waste product found in the blood, called creatinine, is also measured in a separate (creatinine) test. Blood glucose (sugar) tests, such as fasting blood glucose and HbA1c, may also be performed to check for type 2 diabetes, a potential underlying cause of prostate enlargement.

How to Test for Prostate Enlargement

In addition to a DRE and blood and urine testing, the medical team may recommend further tests to reach a definitive diagnosis of an enlarged prostate.

Below are six additional tests commonly used to evaluate a man for BPH.

Symptoms Score Sheets

These forms detail the symptoms patients may be experiencing. They are a valuable resource when diagnosing and directing therapy for patients.

The American Urological Association symptom score is a series of seven questions that doctors ask patients to measure how disruptive or severe BPH symptoms are currently. These questions help pinpoint lower urinary tract symptoms (LUTS), as well as LUTS type and severity.

Each question is scored on a scale of 0 to 5:

0 — not at all

1 — once in a while

2 — less than half the time

3 — about half the time

4 — more than half the time

5 — almost all or all the time

A total symptom score of 0 to 9 is considered mild, a score of 10 to 19 is considered moderate and a score of 20 to 35 is considered severe. The seven questions focus on how often the patient has experienced the following urinary tract symptoms during the past month:

• Having a sensation of needing to push or strain to urinate
• Experiencing difficulty delaying urinating
• Stopping and starting during urination
• Having a weak stream of urine
• Having to urinate again within two hours of the last urination
• Feeling like they are unable to empty their bladder completely during urination
• Needing to get up to urinate after going to bed and before waking for the next day’s activities

Urinary Flow Rate Test

This test assesses the patient’s urine flow rate by measuring the strength of the patient’s stream. A stream of less than 15 milliliters per second (15mL/s) is strongly indicative of an obstruction.

To obtain the measurement, the patient will be asked to urinate into a toilet, urinal or other container that is attached to a machine that measures the flow rate.

Post Void Residual Test

Also known as a bladder scan, this noninvasive test ensures that the patient is emptying his bladder completely. The results of this test determine whether or not a patient is at risk of infection as well as whether anticholinergic medications may be prescribed.

The test may be performed using either a portable or traditional ultrasound scanner that uses high-energy sound waves to reveal how much urine is in the bladder. A second technique places a catheter (tube) in the patient’s bladder immediately after they urinate. The patient is then asked to urinate into the catheter to measure how much urine is still left in their bladder.

Cystoscopy

During a cystoscopy, the care team places a small camera into the urethra and bladder to determine the nature of the prostate anatomy, particularly the length of the prostate, and whether a portion of the prostate has become enlarged enough to block off the stream of urine from the bladder (known as a ball valve effect).

Prostate Volume Measurements

This test places a small probe into the rectum to measure the prostate. Measuring the prostate’s size is important, because it helps doctors determine the most appropriate surgical treatment to perform. For a smaller prostate, many surgical options are available; for larger prostates, only a few options that are recommended have been shown to be most appropriate. The transrectal ultrasound measurement is the most accurate way to determine size.

Prostate-Specific Antigen

Also known as PSA, this blood test can help determine the risk of prostate cancer and is necessary prior to BPH surgery. Operating on a prostate with cancer is risky, and it is important to determine whether there is any concern for cancer before starting treatment.