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Urodynamic assessments

Urodynamic testing is a way to diagnose problems with your lower urinary tract.

What is a urodynamic assessment?

Urodynamic studies (UDS) test how well your lower urinary tract (the bladder, urethra and prostate in men) holds and releases urine. These tests can show how well your bladder works and why there could be leaks or blockages.

I have a question about urodynamic assessments

Why would I have a urodynamic assessment?

Urodynamic assessments are used to diagnose problems with your lower urinary tract. Testing may be recommended if you are suffering from problems such as:

  • Leaking urine
  • Going to the bathroom more frequently than usual
  • Experiencing pain when peeing
  • Having strong, sudden urges to urinate
  • Struggling to completely empty your bladder

What can a urodynamics test help diagnose?

A urodynamic assessment can help diagnose:

  • Stress urinary incontinence
  • Urge urinary incontinence
  • A mixture of stress and urge incontinence

A urodynamics assessment is particularly helpful in identifying other forms of incontinence, and if surgery is being contemplated, it is an important step in assuring that the correct surgery is recommended

What happens during a urodynamics test?

For the urodynamics test, you’ll be asked to lay down on a table, and two thin catheters (tubes) will be inserted into your bladder through the urethra. When the catheters are inserted, you may feel the urge to pee.

One of the catheters is connected to a pressure monitor and the other to a sterile water machine. The pressure monitor measures the pressure inside your bladder, and how much liquid your bladder can hold. Sometimes a third catheter is placed inside the vagina, if you are female, and if you are male it is placed in the rectum. This allows the Consultant to monitor the pressure that the rest of your body puts on the bladder.

Once the catheters are in place, your bladder is slowly filled with water (in some circumstances the water may also contain an x-ray contrast dye). You will be asked by the Consultant to say when you feel the urge to pee.    

During the test the Consultant may ask you to cough, squeeze or strain, to see how your bladder reacts to pressure. After this you will be asked to empty your bladder for the catheters to measure the flow rate and pressure when you pee.

What are the different types of urodynamic assessment?


This test measures how much urine is in your bladder, and how fast this urine comes out (this is your flow rate). During the test, you’ll pee into a special toilet or funnel that has two parts, a container to collect the urine and a scale.

Postvoid residual measurement

Your Consultant will use this test to measure how much urine is left in your bladder after you pee. If you have between 100ml and 150ml of urine left after peeing, your bladder is not emptying completely.


A cystometric test measures three things, how much urine your bladder can hold, how much pressure is built up in the bladder as it stores urine, and how full the bladder is when you start feeling the urge to pee.


Electromyography places special sensors on the skin near your urethra and rectum or on a urethral/rectal catheter to measure the electrical activity in the nerves and muscles in and near your bladder and sphincters.

Video urodynamics

A video urodynamic test uses an MRI or x-ray to take pictures of the bladder while it fills and empties. A special dye may be inserted into your bladder using a catheter.

Are urodynamic tests painful?

Urodynamic tests should not be painful, although at times they may become uncomfortable. The assessment shouldn’t take longer than 30 to 45 minutes.

What to expect after a urodynamics test?

After the catheters are removed you may feel some discomfort such as burning or stinging when peeing, this should settle down after a couple of hours. You may also see blood when you pee, this should settle after a day or so.

There is a small chance that you may develop a urinary tract infection (UTI) caused by inserting the catheters. Your Consultant may advise you to drink extra fluids for 48 hours to flush your system out, this is usually around two and a half litres (eight or nine cups). You may also be advised to cut down on tea and coffee to reduce irritation until your bladder returns to normal.

How do I prepare for a urodynamic assessment?

Some assessments do not require specific preparation, however your Consultant may ask you to arrive with a comfortably full bladder, if this is something you might have difficulty with, you might be asked to arrive a little earlier so that you have the time to drink and fill your bladder.

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Taking care of your body and mind at work or in your personal life and knowing who to ask for help is crucial. Our male health hub is here to provide you with further information and signposting to help.

Our Consultant Urological Surgeons

Mr Garnett

Steve Garnett

Consultant Urological Surgeon

Mr Garnett's specialties include prostate disease, kidney surgery and treatments for Benign Prostatic Hyperplasia (BPH).

Mr Moore

James Moore

Consultant Urological Surgeon

Mr Moore's specialties include overactive bladder and cystitis.

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