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Cystometrogram Overview

written by: Leigh A. Zaykoski•edited by: Leigh A. Zaykoski•updated: 7/31/2009

Cystometrogram (CMG) is a diagnostic test that allows doctors to measure how well the bladder functions. Learn why this test is performed and how the results are used.

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    The cystometrogram is ordered when someone has urinary incontinence, difficulty urinating or urinary retention. It can also be done on people who have diseases that affect bladder function, such as Spina Bifida. The test measures the capacity of the bladder and how much pressure is in the bladder. This helps doctors identify bladder issues such as overactive bladder.

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    No special preparation is required for this test. Wear loose, comfortable clothing that can be removed easily. You will be given a gown to change into once you have arrived in the testing area.

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    During this test, a catheter is inserted into the bladder via the urethra. The opening to the urethra will be cleansed thoroughly and the catheter will be inserted. The catheter has a sensor that can record the filling pressure of the bladder. This is accomplished by filling the bladder with saline so the sensors can detect changes in pressure. The technician will ask you to report feelings of fullness or urinary urgency. Leakage is a common occurrence during this test. If the test is being performed due to urinary retention, you will empty your bladder once the test has been completed. This can help to diagnose the cause of urinary retention so proper treatment can be given.

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    There are very few risks associated with the cystometrogram procedure. Any time a catheter is introduced into the bladder, there is a possibility that infection can occur. An antibiotic may be given before the procedure to prevent infection from developing. Report any fever over 100.5 degrees to your physician and let a medical professional know if you develop chills, bleeding or an inability to urinate normally.

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    The results of this test are used to determine the cause of urinary retention, incontinence, or other bladder problems. Your doctor will discuss the results of the test with you and develop a plan for treatment. Your treatment plan may include medications or surgery to correct any functional abnormalities of the bladder.