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 not needed.
About 240 mL (1 cup) 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 activities.
Why It Is Done
The bladder stress test and Bonney test may be done as part of a physical examination when:
- You have involuntary release of urine upon sneezing, laughing, coughing, or exercising.
- The medical history, physical examination, and urinalysis do not uncover a cause for the incontinence.
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 with medicines.
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 observed.