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Urology Health Topics

This information is approved and/or reviewed by U-M Health System providers but it is not a tool for self-diagnosis or a substitute for medical treatment. You should speak to your physician or make an appointment to be seen if you have questions or concerns about this information or your medical condition. Exención de responsabilidad en Español | Complete disclaimer

Fluorodynamics Study (FUDS)
A fluorourodynamic study allows us to assess how your bladder and sphincter behave while you store urine and when you urinate. This study is often performed in people who have urinary incontinence, have difficulty urinating, and/or who have neurologic diseases that affect bladder function. The test is done to measure bladder capacity, bladder and urethral pressures, and monitor the activity of your sphincter. Problems such as a small capacity bladder, overactive bladder, and high pressure bladder can be identified. Problems with the sphincter, such as weakness or uncoordinated contractions, will be seen. Any obstruction to the flow of urine from the bladder, such as an enlarged prostate, can also be identified.

The actual testing will take about 5 minutes. Preparation for the test will take about 10-15 minutes. You will lie on your back on an x-ray table. Your urethral opening will be cleansed with betadine to eliminate any bacteria on the surface. A catheter will be passed through your urethra and advanced into the bladder. This catheter has two pressure sensors; one sensor will record the pressure in your bladder and the other will record the pressure in your urethra. If your doctor wants to measure your abdominal pressure, a tiny catheter will be inserted into your rectum. Two small adhesive patches (like EKG patches) will be placed on either side of the rectal opening to show us whether the sphincter is relaxed or holding tight.
The bladder will be filled with a clear sterile solution (dye) which can be seen on x-ray. We will ask you to report any sensations that you might have—coolness from the dye, fullness, urgency, pain, etc. We will periodically take x-rays see what your bladder looks like as it fills. You will be able to see these x-ray pictures on a monitor.
If you have urinary incontinence, we may tilt the table upright and ask you to cough and then strain. These maneuvers are performed to try to make you leak urine. We will attempt to replicate the urinary symptoms that you experience in your everyday life. If you have urinary retention, we will ask you to try to urinate. Measuring the bladder and urethral pressures, observing sphincter activity, and watching the shape of your bladder and urethra during leakage and urination will help us identify the problem so that we can recommend treatment options.
You may experience some discomfort when the catheter is passed through the urethra. You may feel pressure when (if) the catheter is inserted into the rectum. Application of the adhesive patches is not painful although you may experience discomfort when they are removed, because they have been taped to your skin.
It is normal to have some irritation when you urinate for 24-48 hours after the study. You may also note a small amount of blood in the urine. You will be given an antibiotic prior to the procedure to guard against infection. You may resume your normal activities immediately following the fluorourodynamic study.
You do not have to do anything special to prepare for this study. You may eat and drink as you normally do. It is done in the clinic and does not require sedation or anesthesia. You may resume your normal activities immediately following the FUDS study. If you are pregnant, you should NOT have this study performed.

Call the clinic nurse if you develop a fever of 100.5 degrees Fahrenheit or higher, chills, or persistent blood in the urine.
Revised by Jerilyn M. Latini, MD , Deborah Crider, NP, Charlene Neer, RN and Dawna D. Allore, RN., May 2006