Post-void residual volume evaluates the amount of urine left in the bladder after urination. It is used to help determine the cause of bladder dysfunction.

What To Expect

There are two ways to test post-residual volume.

In-and-out catheterization involves the insertion of a special tube (catheter) through the tube that carries urine out of the body (urethra) into the bladder. The catheter will drain and measure the remaining urine.

Ultrasound involves the person lying down on while a clinician glides a wand-like instrument (transducer) over the bladder area. The transducer emits sound waves through the skin, which bounce back to the transducer as echoes. The transducer translates the echoes and calculates the amount of urine remaining in the bladder.