The fluid bridge test for urethral incompetence. A comparison of results in women with incontinence and women with normal urinary control.

A new urodynamic test which detects the entry of fluid into the proximal urethra has been used in the investigation of women with urinary incontinence. The test is positive if a "fluid bridge" is established between the bladder and a test point in the urethra. The test results from 30 incontinent patients were compared with those from 30 women with normal urinary control who had been matched for age and parity. Twenty-four of the incontinent women had a positive fluid bridge test (FBT) at 0.5 cm from the bladder neck compared with 6 of the women in the control group. The difference between the test results in the two groups was highly significant (X2 = 19.27, p less than 0.001). In the incontinent patients a diagnosis was made after full clinical examination (which included an attempt to demonstrate stress leakage), cystometry and urethral closure pressure profile measurement. In a number of cases (23%) the only evidence of urethral incompetence was a positive FBT. We conclude that the FBT is a more sensitive index of sphincter weakness than are other non-radiological urodynamic tests.