Uroflowmetry

Uroflowmetry is a simple, diagnostic screening procedure used to calculate the flow rate of urine over time. The test is noninvasive (the skin is not pierced), and may be used to assess bladder and sphincter function.

Uroflowmetry is performed by having a person urinate into a special funnel that is connected to a measuring instrument. The measuring instrument calculates the amount of urine, rate of flow in seconds, and length of time until completion of the void. This information is converted into a graph and interpreted by a physician. The information helps evaluate function of the lower urinary tract or help determine if there is an obstruction of normal urine outflow.

During normal urination, the initial urine stream starts slowly but almost immediately speeds up until the bladder is nearly empty. The urine flow then slows again until the bladder is empty. In persons with a urinary tract obstruction, this pattern of flow is altered, and increases and decreases more gradually. The uroflowmeter graphs this information, taking into account the person’s gender and age. Depending on the results of the procedure, other tests may be recommended by your physician.

Reasons for the Procedure

Uroflowmetry is a quick, simple diagnostic screening test that provides valuable feedback about the health of the lower urinary tract. It is commonly performed to determine if there is obstruction to normal urine outflow. Medical conditions that can alter the normal flow of urine include, but are not limited to, the following:

• benign prostatic hypertrophy (BPH) - a benign enlargement of the prostate gland that usually occurs in men over age 50. Enlargement of the prostate interferes with normal passage of urine from the bladder. If left untreated, the enlarged prostate can obstruct the bladder completely.
• cancer of the prostate, or bladder tumor
• urinary incontinence - involuntary release of urine from the bladder
• urinary blockage - obstruction of the urinary tract can occur for many reasons along any part of the urinary tract from kidneys to urethra. Urinary obstruction can lead to a backflow of urine causing infection, scarring, or kidney failure if untreated.
• neurogenic bladder dysfunction - improper function of the bladder due to an alteration in the nervous system such as a spinal cord lesion or injury
• frequent urinary tract infections (UTI’s)

Uroflowmetry may be performed in conjunction with other diagnostic procedures, such as cystometry and cystography.

There may be other reasons for your physician to recommend uroflowmetry.

Risks of the Procedure

Because uroflowmetry is a noninvasive procedure, it is safe for most persons. The test is usually done in privacy to ensure that the person voids in a natural setting.

There may be risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.

Certain factors or conditions may interfere with the accuracy of uroflowmetry. These factors include, but are not limited to, the following:

• straining with urination
• body movement during urination
• certain medications that affect bladder and sphincter muscle tone

Before the Procedure

• Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
• Generally, no prior preparation, such as fasting or sedation, is required.
• You may be instructed to drink about four glasses of water several hours before the test is performed to ensure that your bladder is full. In addition, you should not empty your bladder before arriving for the procedure.
• If you are pregnant or suspect that you are pregnant, you should notify your physician.
• Notify your physician of all medications (prescription and over-the-counter) and herbal supplements that you are taking.
• Based on your medical condition, your physician may request other specific preparation.

During the Procedure

Uroflowmetry may be performed on an outpatient basis or as part of your stay in the hospital. Procedures may vary depending on your condition and your physician’s practices.

Generally, uroflowmetry follows this process:

1. You will be taken into the procedure area and instructed how to use the uroflowmetry device.
2. When you are ready to urinate, you will press the flowmeter start button and count for five seconds before beginning urination.
3. You will begin to urinate into the funnel device that is attached to the regular commode. The flowmeter will record information as you are urinating.
4. You should not push or strain as you urinate. You should remain as still as possible.
5. When you have finished urinating, you will count for five seconds and press the flowmeter button again.
6. You should not put any toilet paper into the funnel device.
7. The procedure will be concluded at this point. Depending on your specific medical condition, you may be asked to perform the test on several consecutive days.

After the Procedure

Generally, there is no special type of care following uroflowmetry. However, your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.