The reproducibility of urodynamic findings in healthy female volunteers: Results of repeated studies in the same setting and after short-term follow-up

Aim: To assess the immediate (same testing period) and short-term (within 6 months) repeatability of urodynamic (UD) testing in asymptomatic healthy female volunteers. Materials and Methods: Twenty asymptomatic women with a mean age of 41.8 years (30-55) agreed to undergo a UD assessment which consisted of noninvasive uroflowmetry, post-void residual (PVR) measurement, medium-fill cystometry, and pressure flow study with perineal surface electromyographic (EMG) electrodes. The UDS evaluation was repeated immediately without removing the catheters (a two-fill and void study). Sixteen women returned for an identical UD assessment 1-5 months later. Immediate and short-term repeatability of UD parameters was assessed by calculating the coefficient of repeatability (COR). Results: The repeatability of certain parameters of immediate UD testing could not be calculated since there was an apparent influence of the first test on the second (i.e., an apparent accommodation noted in bladder filling volumes). Other immediate UD values (maximum flow, detrusor pressure at maximum flow, voided volume) had high COR values, as did all UD values on short-term testing, indicating relatively poor repeatability. Picking the 'best' pressure flow value (highest flow rate with accompanying detrusor pressure) did not consistently improve the COR values. Conclusions: The lack of repeatability of UD studies likely stems from a combination of the true physiological fluctuations in bladder function and the inherent relative insensitivity of our instruments in conducting these testing. Knowledge of the limitations of current technology is essential in allowing us to better utilize these studies in evaluating our patients and further improving diagnostic strategies.