Urodynamic testing measures how well your bladder is functioning.
Some urodynamic tests are relatively simple and can be done in a doctor's office. Other tests require sophisticated instruments to measure the amount of pressure experienced by the bladder and urethra.
During basic urodynamic testing, the volume of urine and the rate at which the bladder empties are measured as you urinate into a container. A thin, flexible tube (catheter) is then inserted into the bladder through the urethra, and the volume of any urine remaining in the bladder is measured (post-void residual, or PVR). A slight burning sensation may occur when the catheter is inserted.
The bladder may be filled with water through the catheter until you have the first urge to urinate. The amount of water in the bladder is measured at this point. Then more water may be added while you resist urinating until involuntary urination occurs.
More sophisticated testing uses electrodes placed in the rectum to measure the electrical activity of the muscles while the bladder fills.