Urodynamic testing

Urodynamic testing is a diagnostic test used to evaluate and diagnose various bladder and urinary tract conditions, as well as assess how the urinary system functions. It involves a series of measurements and assessments to understand the dynamics of urine storage and release, which can help in diagnosing issues like urinary incontinence, urinary retention, and other urological problems.

Who performs urodynamic testing?

Urologists and gynecologists typically recommend and conduct these tests at clinics, radiology centers, or hospitals. Nurses and physician assistants specializing in urology may conduct urodynamic testing under the supervision of urologists.

What is the purpose of urodynamic tests?

Urodynamic tests are utilized to identify potential issues with the lower urinary tract. These tests may be recommended if the patient experiences symptoms such as

  • Urine leakage
  • Frequent bathroom visits
  • Painful urination
  • Sudden strong urges to urinate
  • Difficulties initiating urination
  • Incomplete bladder emptying
  • Recurrent urinary tract infections

What are urodynamic tests?

Urodynamic tests include a variety of procedures, such as:

  1. Uroflowmetry
  2. Postvoid residual measurement
  3. Cystometry
  4. Leak point pressure measurement
  5. Pressure flow study
  6. Electromyography
  7. Video urodynamic tests

How do you prepare for urodynamic testing and how these tests are performed?

The majority of these tests do not necessitate any specific preparation. However, in some cases, the patient may be requested to drink fluids before the test to ensure the bladder is adequately filled.


  • Measures urine volume in the bladder and the rate of urine flow.
  • Identifies weak bladder muscles or urine flow blockages.
  • Patients urinate in a specialized toilet with a container and scale. The equipment generates a graph showing flow rate changes during urination.
  • The doctors use the graph to assess the peak flow rate and the time it takes to achieve it.
  • Alternatively, the flow rate can be determined by measuring the time it takes to urinate into a specialized container that accurately measures urine volume.

Postvoid Residual Measurement

  • Determines the remaining urine in the bladder after urination.
  • If 100-150 mL or more remains, the bladder may not be emptying completely.
  • This test can be conducted using ultrasound or by draining and measuring the remaining urine with a catheter.

Cystometric Test

  • Assesses bladder capacity, pressure during urine storage, and fullness when the urge to urinate is felt.
  • Involves bladder emptying with a catheter and gradual filling with warm water.
  • The patient describes bladder sensations and urge to urinate, while water volume and bladder pressure are recorded.
  • During the test, coughing or straining may be requested to check for changes in bladder pressure or urine leakage.
  • This test can identify abnormal bladder contractions.

Leak Point Pressure Measurement

  • Measures bladder pressure when sudden urine leakage occurs during the cystometric test.
  • Aids in understanding the type of bladder problem.
  • The patients may be instructed to cough, change position, or attempt exhalation while holding the nose and mouth to assess sphincter function.

Pressure Flow Study

  • Assesses the pressure needed for bladder emptying and the rate of urine flow at that pressure.
  • Conducted after the cystometric test while emptying the bladder.
  • Helps identify any bladder outlet blockages resulting from conditions like prostate enlargement or urinary incontinence surgery.


  • Suggested when urinary issues are related to nerve or muscle damage.
  • Measures electrical activity in bladder and sphincter muscles and nerves.
  • Special sensors are placed near the urethra and rectum or on a catheter to record muscle and nerve activity.
  • Aids in determining if messages to the bladder and pelvic floor muscles coordinate correctly.

Video Urodynamic Tests

  • Combines cystometry, uroflowmetry, and X-ray cystography into a comprehensive test.
  • Utilizes advanced digital equipment to measure urine flow and pressure in the bladder and rectum.
  • Captures images of the bladder as it fills and empties. This evaluation provides insights into bladder and urethral function and reveals the bladder’s size and shape.
  • If X-rays are used, a contrast medium is introduced into the bladder to enhance image clarity.

After urodynamic tests

After undergoing urodynamic testing, the patient may experience mild discomfort or soreness while urinating, but this should only last for a few hours. It is normal to see a small amount of blood due to the catheter, which is usually temporary. Drinking plenty of water is recommended to alleviate these symptoms.

The doctor might suggest additional measures to ease any discomfort, such as taking a warm bath or using a warm, damp washcloth over the urethral opening. If needed, over-the-counter pain medication may also be advised.

In some cases, the doctor may prescribe an antibiotic to prevent infection, but this is not always necessary. However, if signs of infection like fever, chills, or severe pain are observed, it is crucial to promptly contact a doctor for a thorough evaluation and appropriate management.

Following the procedure, the results of simple tests such as cystometry and uroflowmetry are usually available immediately.

On the other hand, for more complex tests like electromyography and video urodynamic tests, it may take a few days for the results to be processed and ready for review.


  1. National Institute of Diabetes and Digestive and Kidney Diseases. Urodynamic Testing. Available from: https://www.niddk.nih.gov/health-information/diagnostic-tests/urodynamic-testing
  2. Urology Care Foundation. Urodynamics. Available from: https://www.urologyhealth.org/urology-a-z/u/urodynamics
  3. Cleveland Clinic. Urodynamic Testing. Available from: https://my.clevelandclinic.org/health/diagnostics/15684-urodynamic-testing

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