A post-void residual (PVR) test is typically conducted by using a non-invasive ultrasound or a catheter. In order to see the bladder and gauge how much urine is still in it, a portable device is put on the lower abdomen for an ultrasound test. As an alternative, any leftover urine can be drained from the bladder through the urethra and measured using a catheter. The process, which is usually short and painless, gives important information regarding how much pee is still in the bladder after voiding.