Cystometry is a test that measures the pressure inside of the
bladder to see how well the bladder is working.
Cystometry is done when a muscle or nerve problem may be causing problems with
how well the bladder holds or releases urine.
Urination is a
complex process. As the bladder fills, nerves in the bladder wall send a
message to the
spinal cord and brain that you need to urinate. In response, your spinal cord
sends a signal for the bladder to contract (voiding reflex). When you hold in
your urine, your brain is overriding this reflex. When you allow the reflex to
occur, urination occurs. A problem affecting this nerve pathway or the muscles
of the bladder wall can cause bladder dysfunction.
cystometry, your bladder is filled with water or gas to measure its ability to
hold in and push out the water or gas. Medicine may also be given to see
whether your bladder contracts or relaxes normally in response to the medicine.
A small tube (catheter) can be placed in your
rectum to measure pressure as the bladder fills. A
small pad or needle may be placed near your
anus to measure muscle function in this area.
Why It Is Done
Cystometry is done to:
- Find the cause of problems with the
bladder or the muscle that holds urine in the bladder
(bladder sphincter). Problems in one or both of these areas may cause
uncontrolled urine leakage, an urgent feeling that you have to urinate, or a
weak urine stream.
- Measure how much urine your bladder can store and how much urine
remains in your bladder after you feel you have completely emptied it (residual
- Help you and your doctor make decisions about how to treat your
- See how well the bladder works in people with
progressive neurological diseases, such as
How To Prepare
Tell your doctor if you:
- Are taking any medicines. Some medicines and herbal supplements
can affect bladder function.
- Are or might be pregnant.
- Have symptoms of a
urinary tract infection, such as pain or burning with
urination, foul-smelling or cloudy urine, or an urge to urinate more often than
Talk to your doctor about any concerns you have regarding
the need for the test, its risks, how it will be done, or what the results will
mean. To help you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
Cystometry is done in a doctor's
office or hospital urology department by a
gynecologist, or other trained health
You will need to take off most of your clothes below
the waist. You will be given a cloth or paper covering to use during the
- At the beginning of the test, you will be asked to urinate into a
toilet that is connected to a machine called a uroflowmeter. This machine
measures how much urine passes and how long it takes. The time and effort
needed to start the flow of urine, the number of times you start and stop the
flow of urine, and the presence of dribbling near the end of urinating are also
- Next, you will be asked to lie on your back on an examining
table. After the
urethra is thoroughly cleaned, a well-lubricated thin,
flexible tube (catheter) is gently inserted and slowly moved into
your bladder. Any urine remaining in your bladder (residual volume) will be
drained and measured.
- Next, a catheter is used to fill your bladder with sterile,
room-temperature water. The catheter is also attached to a device called a
cystometer, which measures how much your bladder can hold and the pressure in
your bladder. You will be asked to report any feelings such as warmth, bladder
fullness, or an urge to urinate. The process may be repeated.
- Sometimes a gas (usually carbon dioxide) is
used instead of water.
contrast material may be used if
X-rays are taken during the test.
- Another catheter may be placed in your rectum to
measure the pressure in your abdomen as your bladder fills. A small pad or
needle may be placed near your anus to measure muscle function in this
- Each time your bladder is filled, you will be asked to report
when you first feel the urge to urinate. Your bladder will then continue to be
filled until you report that you feel you must urinate. Then the catheter will
be used to drain the bladder, or you will be asked to urinate.
- After all the liquid is drained out of your bladder, and if no
additional tests are required, the catheter is removed.