This page provides information for patients due to have a urodynamic investigation. We want you to understand the risks and benefits, how to prepare for the investigation and what to expect both during and after the test.

What are urodynamics?

The word ‘urodynamics’ covers a range of tests designed to show how well your bladder is working. A standard urodynamic investigation is a test to assess your bladder function. Fluid is run into your bladder and the pressure response to filling and emptying your bladder is measured using a small catheter (tube).

Urodynamic investigation is carried out for different types of bladder symptoms. This is a common procedure that patients have before some types of urological or gynaecological surgery.

The purpose of the test is to help us:

  • diagnose the cause of your bladder symptoms.
  • find out why your bladder may not be working normally.
  • offer you an individual treatment plan that is best for your symptoms.

There are currently no alternatives available which will give us the information provided by the test.

Before the investigation

Please let us know if you have any allergies, especially to latex or if you have any problems with your mobility.

We are unable to perform urodynamics if you have a symptomatic urinary tract infection. If you are prone to urinary tract infections your urine must be tested 7 to 10 days before your urodynamic investigation date. Please contact your GP’s surgery to arrange.

Your GP will decide if you need a course of antibiotics to take a few days before the urodynamic test and for a few days after the test.

Preparing for the investigation


Please stop taking any medication you are taking for your bladder or prostate (for men) 7 days before your appointment as these medications can affect the results of the test.

The investigation may have to be rescheduled if the medication has not been stopped before the test.

Below is a list of the common bladder and prostate medications that should be stopped:

Prostate medication

  • Alfuzosin (Xatral®, Xatral SR®, Xatral XL®)
  • Doxazosin (Cardura®)
  • Dutasteride (Avodart®)
  • Indoramin (Doralese®)
  • Prazosin (Hypovase®)
  • Tamsulosin (Flomax®, Flomaxtra XL®, Combodart®)
  • Terazosin (Hytrin®)
  • Finasteride (Proscar®)

Bladder medication

  • Desmopressin (Noqdirna)
  • Fesoterodine Fumarate (Toviaz®)
  • Flavoxate Hydrochloride (Urispas®)
  • Oxybutynin Hydrochloride (Cystrin®, Ditropan®, Ditropan XL®, Lyrinel XL®)
  • Mirabegron (Betmiga®)
  • Propiverine (Detrunorm®, Detrunorm XL®)
  • Solifenacin Succinate (Vesicare®)
  • Tolterodine Tartrate (Detrusitol®, Detrusitol XL®)
  • Trospium Chloride (Regurin®, Regurin XL®)
  • Kentera (Oxybutynin transdermal patch®)

Combined medication

  • Tamsulosin and Solifenacin (Vesomni®)

No special preparations are needed for the test. You are not required to drink extra fluids before the test so please eat and drink as normal.

We would like you to arrive for the test with a comfortably full bladder. If this is too difficult for you to do, please ignore this request. It is helpful to have a pre void test (to measure the amount of urine remaining in your bladder after passing urine) before the urodynamic test but it is not essential.

If you need to pass urine urgently while waiting in the clinic, please let the reception staff know and they will contact the clinical nurse specialist who will take you to the urodynamic toilet.

Please fill in the frequency/volume bladder chart. For our male patients; can you also fill in the International Prostate Symptom Score (IPSS) form. The charts/forms will be included with your appointment letter. It is important that you bring the completed charts/forms with you to the appointment.

Record the information listed below for at least 3 days on the frequency/volume chart:

  • The amount of fluids you drink over 24 hours.
  • What type of fluid you drink.
  • How many times you pass urine in 24 hours.
  • What volume of urine you have passed each time - use a measuring jug (you may need to buy one).
  • If you have leaked urine (wet or dampness or pad).

It is important that you fill in this chart as accurately as possible, as this data gives us valuable information when performing the test and understanding your bladder problem.

If the medication you are taking is not listed on the previous pages or if you are not sure whether or not to stop your medication, please contact Gloucestershire Bladder and Bowel Health or the Urogynaecology Department depending on who is managing your investigation. The telephone numbers are at the end of this page.

What does the investigation involve?

You will have a short consultation with the urodynamic specialist nurse who manages the clinic. The specialist nurse will ask you some questions about your bladder symptoms. Some questions may be intimate and you may have answered them before, but they are important in making a diagnosis of your problem. The consultation is a good opportunity to talk over any concerns or worries that you may have.

The specialist nurse will also ask to see your frequency/volume bladder chart and the International Prostate Symptom Score (IPSS).

The nurse will explain what is going to happen during the investigation.

You will then be asked to pass urine (in private), into the urodynamic toilet which will measure information important to us, such as the rate at which your urine flowed and the amount of urine you passed.

After you have passed urine, the nurse will carry out a painless ultrasound scan on your bladder to record any urine that may be left in your bladder. For this scan, you will be asked to lie down on a couch and uncover your abdomen (stomach). A small amount of gel will be placed on your abdomen. A hand-held probe will be placed on top of the gel to scan and record any leftover urine in the bladder. The scan will take only a couple of moments and is not painful.

During the investigation

At the start of the urodynamic investigation, a fine sensor, catheter tube/wire (sterile) will be put into your bladder through the urethra (the tube through which urine is passed). Another sensor will be placed into the rectum (back passage) or vagina (used occasionally for women). Placing these tubes/wires should not be painful as a lubrication gel is used to reduce any discomfort. Some patients may find this part of the investigation slightly uncomfortable or a little embarrassing. The nurse specialist will try to reduce this as much as possible.

If you have a colostomy, the rectal tube/wire will be placed into your stoma. Please bring an extra stoma bag with you, so that you can change your stoma bag after the investigation.

If you have a urethral catheter in place, this will be removed for the investigation. Please bring with you a spare catheter with a spare urine bag or valve as a catheter may still be needed after the investigation.

When the sensor tubes/wires are in place, they are attached to a computer and your bladder activity will be measured as it fills and empties.

Your bladder will be filled with sterile saline (salt water) through the fine tube until you feel the need to pass urine. You will be asked to cough at various stages during the investigation; this is to show if the sensors are recording correctly. The nurse specialist will try to reproduce the bladder symptoms that you are currently having by getting you to cough, laugh or listen to running water. You will also be asked a series of questions such as your first desire to pass urine or whether you experience any urgency.

When the nurse specialist feels that enough information has been collected, you will be allowed to empty your bladder into the specially adapted urodynamic toilet (in private). This toilet will measure the flow rate and volume of urine passed. Once this is done, the sensor tubes/wires will be gently taken out and you will be offered some wet wipes and dry wipes so you can have a wash and make yourself comfortable and get dressed in privacy.

You should allow 1 hour for the test.

After the investigation

The result of your investigation will be discussed with you by the urodynamic nurse specialist, along with any treatment you may need.

The doctor or consultant, who arranged the urodynamic investigation for you, will receive a report. They will then send you a letter with the results of the investigation and/or a follow-up appointment.

After the test you may experience symptoms of discomfort in your bladder and/or urethra for a short time, but these should settle down. We advise you to drink extra fluids for 24 hours, as this will help to dilute your urine, reduce urethral irritation and reduce the risk of infection. Try to drink 2 to 4 extra glasses of fluid (non-alcoholic).

Side effects of the investigation

Some patients may have one or more of the following side effects:

Urinary Tract Infection (UTI)

Even though the procedure was carried out in a sterile manner, putting anything into the bladder carries the risk of infection. Signs of an infection to look out for include a raised temperature, feeling hot and cold or feverish, feeling a burning sensation when passing urine (the urine may even be smelly) or just feeling unwell. Some patients may also need to pass urine very often or urgently. If you think you have an infection, please contact your GP and tell them you have had a recent urodynamic investigation. You may need a course of antibiotics.


There is a small chance of bleeding; you may see blood in your urine after this test. This is because a fine tube was put into your bladder during the test. This is nothing to worry about and should go away within 24 to 48 hours. If the bleeding does not stop or it becomes heavy then please contact your GP for advice.

Women having the investigation while having a period

If you are expecting your period at the time of the investigation, you do not have to rearrange your appointment unless you are bleeding heavily or if you would rather have the investigation at another time.

Changing or cancelling your appointment

It is important to contact the Gloucestershire Bladder and Bowel Health or Urogynaecology Department as soon as possible if you need to change or cancel your appointment. We will then be able to offer that appointment to another patient and arrange a new date and time for you.

Contact information

We hope that this information helps you feel more prepared for the investigation but if you have any further questions, please contact Gloucestershire Bladder and Bowel Health or the Urogynaecology Department depending on who is managing your investigation.

Gloucestershire Bladder & Bowel Health (Adult)

Oakley Suite, 2nd Floor Centre Block, Cheltenham General Hospital, Sandford Road, Cheltenham, GL53 7AN

Tel: 0300 422 5304


Urogynaecology Department

Gynaecology Outpatients, Women’s Centre, Great Western Road, Gloucester GL1 3NN

Tel: 0300 422 6246

Further information

Bladder & Bowel UK


International Prostate Symptom Score (IPSS)


The British Association of Urololgical Surgeons (BAUS)

Urodynamic Studies (pressure tests on your bladder)



Printable version of this page

Urodynamic investigation GHPI0622_06_23 Department: Urology Review due: June 2026 PDF, 333.8 KB, 8 pages
Reference number GHPI0622_06_23
Department Urology
Review due June 2026