A urodynamics study is a series of tests that gives your doctor a detailed look at the function of your bladder and urethra. These tests can help your doctor evaluate any problems you may be having with storing urine or voiding (eliminating) urine from your body.

The lower part of the urinary tract includes the bladder (which stores urine until you’re ready to release it) and the urethra (the canal that carries urine from the bladder out of the body). Signals from the brain tell the sphincter (muscles around the opening of the bladder) when to relax and the bladder when to contract to let urine flow out of the body.
Possible problems that you may have with storing or voiding urine include the following:
You may be incontinent (leak urine).
Your bladder may not empty completely.
You may have symptoms, such as the frequent need to urinate or a constant, urgent need to urinate.
Your urine stream may be intermittent or weak.
You may have persistent urinary tract infections.
Tell your doctor which medications you’re taking, and ask whether you should stop them before the study. You may be asked to keep a diary of your urination habits for a few days before the study. This diary can be a helpful part of your evaluation. Ask whether you need to arrive for the study with a full bladder.