In a patient who complains of urinary incontinence, a cystometrogram is performed to

As a catheter is introduced for performing a cystometrogram, measurement of residual urine is obtained. During the cystometrogram, a normal first sensation is of fullness felt at 100 mL. Urge is felt at approximately 350 mL, with maximum capacity at 450 mL. The primary reason to perform a cystometrogram is to rule out uninhibited detrusor contractions. The cystometrogram is a urodynamic test, and it cannot determine whether ureterovesical reflux exists. The degree of reflux can be evaluated with the voiding cystogram, a radiologic test.