The amount of leftover (residual) urine can be measured by draining the
bladder with a thin flexible tube (catheter) or by using ultrasound. The
catheter method has a slight risk of causing infection or injury to the tube
leading from the bladder (urethra). But the catheter method is safe when
done carefully. And it may be less expensive than ultrasound.
How this information was developed to help you make better health decisions.