Bladder Scan for Residual Urine

Description of bladderscan (ultrasound) for residual urine

The bladderscan is a form of ultrasound that is used to determine the amount of urine in the bladder without the need to pass a tube (catheter) into the bladder. Ultrasound is the same as sonogram, echogram or sonar. A special probe (like a microphone) is placed on the skin after the skin is prepared with a special jelly. The picture is a reflection of sound waves, and is painless with no injections needed. This is a test that truly does not hurt and is safe. With the bladderscan we are able to get a fairly clear view of the outline of the bladder in all three dimensions. With these measurements the bladderscan is able to accurately calculate the bladder volume.

Possible risks

There are no risks with this procedure.


There is no prep with the bladderscan.

You need to be able to urinate just before the test. You will usually do this after checking in with the receptionist. Unless absolutely necessary, don't urinate before leaving home or before you get to our office; we may need a specimen. On occasion, the amount in the bladder before urinating is measured and then compared to the amount left in after urination.