What does the number on a bladder-emptying scan mean?
The number on a bladder scan after you urinate estimates how much urine is still in your bladder. The report may call it a post-void residual, or PVR, and list it in milliliters. Its meaning depends on how soon the scan was done, how much you urinated, whether that void felt typical, and what symptoms brought you in.
Put the reading in context
A scan taken soon after a normal void answers a different question from one taken after you had to stop early, felt rushed, or waited before the scan. Tell the clinician if it was hard to urinate on command or if the amount was smaller than usual. A repeat measurement may help if the result is unexpected or the visit conditions were unusual.
A residual can help a clinician assess bladder emptying. Other pieces of the evaluation help distinguish possible reasons, such as resistance to urine flow or a bladder that is having trouble pushing urine out. Ask whether your result changes the next step and whether another test would answer a specific question.
Bring the reading and the circumstances
Write down the measurement, when it was taken, and whether you strained or felt you still had to go. Bring earlier reports and a list of medications, including recent changes. If you suddenly cannot pass urine, seek urgent medical care. Read more about urinary retention.