A bladder stress test simulates the accidental release of urine
(urinary incontinence) that may occur when you cough,
sneeze, laugh, or exercise.
A Bonney test is done as part of the bladder stress test,
after the doctor verifies that urine is lost with coughing. It is
similar to the bladder stress test except the bladder neck is lifted slightly
with a finger or instrument inserted into your vagina while the bladder stress
is applied. This checks to see if incontinence is the result of the bladder
neck being pushed down too far by the stress.
While you are lying down, a thin, flexible tube called a catheter
is inserted into the bladder through the
urethra. A slight burning sensation may occur when the
catheter is inserted. If your bladder is already full, using the catheter is
1 cup (236.6 mL) of a fluid is
put into the bladder through the catheter. The catheter is then removed,
and you are asked to cough. The doctor looks for any fluid loss and notes the
time interval between the stress (coughing) and the fluid loss. The stress test
may be repeated while you are standing up.
If the release of fluid is not detected during the bladder stress
test or Bonney test, it may be repeated while you are standing. An absorbent
pad may be worn to collect any urine released while you go about your daily
Why It Is Done
The bladder stress test and Bonney test may be done as part of a
physical exam when:
You have involuntary release of urine upon
sneezing, laughing, coughing, or exercising.
The medical history,
physical exam, and urinalysis do not uncover a cause for the
Stress incontinence is suggested if fluid leaks after
coughing. A person who loses fluid during the stress test may be helped by
surgery that raises the bladder neck.
Fluid loss that is not immediate (that is, it occurs several
seconds after coughing) indicates that abnormal bladder muscle contractions are
occurring. This suggests
urge incontinence. These contractions may be treated
What To Think About
It is not uncommon for a woman to be able to hold back the fluid
(be continent) while doing this test lying down but to lose fluid (become
incontinent) while standing up, due to the effect of gravity.
It is possible for a woman to have both stress incontinence and
urge incontinence at the same time. Successful treatment of stress incontinence
can sometimes help urge incontinence too.
The Bonney test is difficult to standardize. Because of this, the
outcome is not reliable. It is important during the test to elevate the tissue
on either side of the bladder neck rather than to compress the bladder neck
itself. If urine leakage is stopped when a finger or instrument is inserted
into the vagina, it may be a result of the
urethra being pinched shut rather than a result of the
proper elevation of the bladder. If the Bonney test is being used to find out
whether surgery is needed, the doctor who does the test must be very
experienced to get a reliable result.
It may be embarrassing to some people to urinate while being