What is urodynamic testing? Dr. Craig Comiter, an expert on female urology at the University of Arizona Health Sciences Center in Tucson, has your answers: 

Q: What is a urodynamic test?

A: This is a test of the function of the bladder’s storage and emptying abilities. It’s used when a diagnosis is in question. In other words, why does the patient leak urine? Could it be from an overactive or underactive bladder, or from a weak sphincter mechanism? The test can also show if the nerves and muscles needed for urination are working properly.

Q: How does the test work?

A: The bladder is filled with sterile water using a catheter with a separate pressure-transducer. The patient tells us when she feels the urge to urinate, so we then know how much urine she can hold. The pressure measurement tells us if the bladder is relaxed or contracting. We also measure leak point pressure, or the pressure at which the patient leaks.

Q: Who performs this test, and is it painful?

A: The test is performed by a doctor, nurse, or technician, but it’s best if the doctor does it. The discomfort is minimal, just the catheter passed gently into the bladder. The action of filling the bladder doesn’t hurt, and the patient simply strains during the measurement of the leak point pressure, then urinates at the end of the test. 

Q: What are the risks with this procedure?

A: Sometimes we use a contrast dye and X-ray equipment to better view the anatomy of the bladder, to see any prolapse of the bladder and so forth. The risk is minimal, with only a one-percent infection rate, which we can reduce with oral antibiotics.