Diagnostic Tests

International Prostate Symptoms Score

An indexing tool called the International Prostate Symptoms Score (IPSS) can help evaluate the key lower urinary tract symptoms. As opposed to laboratory tests or other objective tests, this scoring system measures the patient's own experience. The higher the score, the more severe the conditions. It is useful for many reasons:

• The patient's score on this test gives a highly accurate assessment of the effect of lower urinary tract symptoms on the quality of a man's life.
• It is a reasonable basis from which the patient and doctor can discuss treatment options.
• The index is also often used to gauge treatment outcomes and may be a better indicator of success than objective tests, such as the measurement of the prostate gland or the rate of urine flow.

Limitations. The IPSS is useful only as a measure of symptom severity, and has the following limitations:

• Other conditions can produce similar scores, so the test is not used as a diagnostic tool for BPH.
• The index does not include other urinary symptoms, such as dribbling and incontinence or sexual health, that are important for quality of life. At the very least, the patient should have a frank discussion with his doctor if such symptoms are present and affect his life.
• It also does not reflect regional or ethnic differences that can vary the responses to these symptoms.

Other Indexing Systems

Other indexing systems, such as Symptom Problem Index (SPI) and the BPH Impact Index (BII), which gauge different quality-of-life and disease issues, are being used in addition to the IPSS to help assess the patient.

Physical Examination

Digital Rectal Exam. The digital rectal exam is used to detect an enlarged prostate. The doctor inserts a gloved and lubricated finger into the patient's rectum and feels the prostate to estimate its size and to detect nodules or tenderness. The exam is quick and painless, but embarrassing for some, and far from infallible. The test helps rule out prostate cancer or problems with the muscles in the rectum that might be causing symptoms, but it generally underestimates the prostate's size. It is never the sole diagnostic tool for either BPH or prostate cancer.

Other Physical Examinations. The doctor will usually press on and manipulate (palpate) the abdomen and sides to detect signs of kidney or bladder abnormalities. The doctor will also check for signs of anemia or swelling in the legs and arms. Certain procedures that test reflexes, sensations, and motor response may be performed in the lower extremities to rule out possible neurologic causes of bladder dysfunction.

Uroflowmetry

To determine whether the bladder is obstructed, an electronic test called uroflowmetry measures the speed of urine flow. The test cannot determine the cause of obstruction, which can be due not only to BPH but possibly also to problems in the urethra, weak bladder muscles, or other causes.

• The patient is instructed not to urinate for several hours before the test and to drink plenty of fluids so he has a full bladder and a strong urge to urinate.
• To perform this test, a patient urinates into a special toilet equipped with a uroflowmeter.
• It is important that the patient remains still while urinating to help ensure accuracy, and that he urinates normally and does not exert strain to empty his bladder or attempt to retard his urine flow.
• Many factors can affect urine flow (such as straining or holding back because of self-consciousness) so experts recommend then that the test be repeated at least twice.

Q[max]. The rate of urine flow is calculated as milliliters of urine passed per second (mL/s). At its peak, the flow rate measurement is recorded and referred to as the Q[max]. The higher the Q[max], the better the patient's flow rate. Men with a Q[max] of less than 12 mL/s have four times the risk for urinary retention than men with a stronger urinary flow.

The Q[max] measurement is sometimes used as the basis for determining the severity of obstruction and for judging the success of treatments. It is not very accurate, however, for several reasons:

• Urine flow varies widely among individuals as well as from test to test.
• The patient's age must be considered. Flow rate normally decreases as men age, so the Q[max] typically ranges from more than 25 mL/s in young men to less than 10 mL/s in elderly men.
• The Q[max] level does not necessarily coincide with a patient's perceptions of the severity of his own symptoms.

Urinalysis

A urinalysis can detect signs of bleeding or infection. A urinalysis involves a physical and chemical examination of urine. In addition, the urine is spun in a centrifuge to allow sediments containing blood cells, bacteria, and other particles to collect. This sediment is then examined under a microscope. Although urinary infection is uncommon in younger men, it occurs more frequently in older men, particularly those with BPH. A urinalysis also helps rule out bladder cancer.

Pre and Post Massage Test (PPMT)

To rule out prostatitis (infection or inflammation of the prostate gland), a simple test called the Pre and Post Massage Test (PPMT) is about 90% accurate. This test requires two cultures and microscopic examinations of urine samples taken before and after massage of the prostate gland. To massage the prostate the doctor simply inserts a gloved finger into the rectum and presses several times on the prostate. The following results are indicated by findings on cultures after massage:

• Category II prostatitis (Chronic bacterial). Bacteria are found on post-massage.
• Category IIIA prostatitis (Inflammatory chronic pelvic pain syndrome). Leukocytes or other cells are found that indicate inflammation.
• Category IIIB prostatitis (Noninflammatory chronic pelvic pain syndrome). No signs of inflammation or bacteria.

Serum Creatinine

In men with symptoms, blood tests can measure a substance called serum creatinine, which is a marker for kidney trouble. Kidney problems exist in an average of 13.6% of BPH patients. Studies have reported rates as high as 30% and as low as 0.3%.

PSA Test for BPH and Prostate Cancer

A PSA test measures the level of prostate-specific antigen (PSA) in the patient's blood. It is the standard screening test for prostate cancer. A PSA is recommended annually for all men over 50 years old and for men over 40 who are at high risk for prostate cancer.

BPH itself can also raise PSA levels, but the test has generally been optional for men with suspected BPH. One 2000 study indicated that PSA levels may be good predictors of future prostate growth in men with BPH. In the study, men with the lowest PSA level groups (0.2 to 1.3 ng/mL) had prostate growth rates of only 0.7 mL per year while those in the high PSA groups (3.3 to 9.9) had growth rates of 3.3. mL per year. Other research has detected a specific molecular form of PSA, called BPSA because it may be a specific marker for BPH. Such findings could eventually lead to a shift from focusing on symptoms and flow rates for diagnosis to a more specific and possibly preventive approach.

Certain treatments for BPH, including the drug finasteride (Proscar) and the surgical procedure transurethral resection of the prostate (TURP), can reduce PSA levels and possibly mask the existence of prostate cancer.

A more recent test identifies so-called free PSA, which is found in lower levels when prostate cancer is present and in higher levels with benign prostate hyperplasia. This may be more accurate than total PSA, regardless of whether a man is taking finasteride or not.

Postvoid Residual Urine

One of the important tests for urinary incontinence is the postvoid residual urine volume (PVR), the amount of urine left after urination. Normally, about 50 mL or less of urine is left; more than 200 mL is a definite sign of abnormalities. Measurements in between require further tests. The most common method for measuring PVR is with a catheter, a soft tube that is inserted into the urethra within a few minutes of urination. PVR can also be measured using transabdominal ultrasonography.

Ultrasound

Ultrasound of the prostate does not require a catheter and gives an accurate picture of the size and shape of the prostate gland. Ultrasound is very beneficial when planning surgery and determining treatment options and gauging their effectiveness. Ultrasound may also be used for detecting kidney damage, tumors, and bladder stones. Ultrasound tests of the prostate generally use one of two methods:

• Transrectal ultrasonography (TRUS) uses a rectal probe for assessing the prostate. TRUS is significantly more accurate for determining prostate volume. It can sometimes detect cancer.
• Transabdominal ultrasonography uses a device placed over the abdomen. It can give an accurate measure of postvoid residual urine and is less invasive and expensive than TRUS.

Filling Cystometry

Filling cystometry, also called cystometrography, is usually used for patients who cannot urinate and in whom nerve damage or injury of the bladder is suspected. The test is used to determine the absence or presence of a condition called uninhibited detrusor contractions (UDC), which often occurs in men with storage urinary tract symptoms. The detrusor is the group of muscle fibers that cover the outside of the bladder. The test does not add much information to results from less invasive tests and is not used routinely.

Urethrocystoscopy

A urethrocystoscopy, also called cystourethroscopy, may be performed in men diagnosed with BPH, particularly if they are surgical candidates or if other urinary tract problems are suspected. Such problems include blood in the urine, infection, interstitial cystitis, bladder cancer, or prior surgery or injury. The doctor can determine the presence of a number of structural problems, including enlargement of the prostate, obstruction of the urethra or neck of the bladder, anatomical abnormalities, or the presence of stones.

Procedure. In this procedure, a flexible or rigid fiberoptic tube (an endoscope) is inserted into the urethra to allow doctors to view the lower urinary tract.

Complication. The procedure is not without risks. Complications are uncommon but can include allergic response to the anesthetic, urinary tract infection, bleeding, and urine retention.

Intravenous Excretory Urography

An x-ray called an intravenous excretory urography (IVU) is an invasive test that is used only when complications in the upper urinary tract, particularly in the kidney, are suspected. Alternatively, an abdominal ultrasound plus a normal x-ray may be as useful as IVU for most patients with suspected upper urinary tract problems.

Complications and Side Effects. If there is any danger of kidney failure, the test should not be performed, since it can exacerbate the condition. Severe side effects of the test occur in 0.1% of patients.

Differentiating between BHP and Interstitial Cystitis (IC)

Some doctors believe that a number of men may be incorrectly diagnosed with BPH when they have interstitial cystitis (an inflammation of the bladder that may be associated with allergic or autoimmune response). The potassium sensitivity test is sometimes used to diagnose IC. Some experts believe this test missed too many IC patients, although a 2001 study concluded that a combination of potassium sensitivity and urodynamic tests is useful in distinguishing between BPH and interstitial cystitis.

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Review Date: 6/26/2006
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital