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Flow rate test

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What do I need to do before I arrive for the flow rate test?

You can eat and drink as normal before you arrive for the test. Your bladder should be comfortably full for the test. If you are unable to travel with a full bladder then you can drink in the department to fill up your bladder. You can arrive early for your appointment if needed in order to do that. Please be aware that it may take up to 2 hours for your bladder to fill up.

Please do not use the toilet before you are seen.

Please let us know in advance if you have any mobility issues.

What is a flow rate test?

A flow rate test is a test that records the rate and volume of urine that you pass. It is carried out to assess the changes you have experienced in your usual flow of urine. You will be asked to pass urine into a machine in a private designated room. The results will be recorded and printed outside the room. You will also have a scan of your bladder before and after you void.

What does the bladder scan involve?

A bladder scan records the volume of urine that is in your bladder. You will be asked to lie down on a couch and the scan will be performed on your lower abdomen. This will show the amount of urine left in your bladder.

Why do I need a flow rate test?

The flow rate test will enable your doctor or nurse to assess how well you are emptying your bladder, the rate at which the flow of urine comes out and also the amount you void. This helps to decide the most appropriate treatment or you may need further investigations.

Are there any risks involved with this test?

There are no side-effects or risks involved with this test. You can return back to normal activities straight after.

Flow rate test machine

Flow rate machine

How long will I be at the clinic?

It is not possible to say how long it will take to complete the test. It will depend on when your bladder is full enough to perform a satisfactory flow test. Ideally, you should have a minimum of 200mls in your bladder to go ahead with the test.

Please be prepared to wait if you are not ready to have the test. You may bring some reading material with you to pass the time.

What happens after the test?

You will be able to go back to normal activities after the test. The results will be printed off and inserted into your Hospital notes. Then your health care professional will review and make a plan of care for yourselves.

Please let us know if you have a:

  • History of low sodium
  • Take water tablets
  • Have kidney disease
  • On fluid restriction
  • Have a urinary catheter
  • Unable to stand unaided.

Useful contact details

Princess Royal Hospital 01444 441881, extension 67752, 63667, 68301 or 65457.

This information is intended for patients receiving care in Brighton & Hove or Haywards Heath.

The information here is for guidance purposes only and is in no way intended to replace professional clinical advice by a qualified practitioner.

Publication Date: October 2021

Review Date: July 2024

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