A CMG is a test used to determine how the bladder reacts to sterile water that is instilled into the bladder through a catheter. A computer tracts and records the pressures exerted in the bladder during filling, straining and voiding. This is done with two small pressure sensors placed in the bladder and the rectum with small tubes.

This test is usually used to help determine the function of the bladder, the prostate in males, and the urethra in medical conditions involving bladder control problems such as urgency, frequency, incontinence, obstruction, etc. The results are recorded and then evaluated by the physician.

Depending on the results, specific treatments for these conditions will be recommended.