Pressure-flow studies: Short-time repeatability

The within and between examination variation in selected test parameters an d test results in repeated pressure-flow studies was determined in a prospe ctive study of consecutive pressure-flow examinations in 22 patients. The p atients were pressure-flow tested twice within a month. Furthermore, it was evaluated whether there was a systematic change in the measured parameters during retesting. By using the Abrams-Griffiths nomogram, patients were cl assified as obstructed, equivocal, or unobstructed. Within and between exam ination variations in classification were evaluated. We found a systematic Variation in P-det.Qmax during testing, which in the absence of statistical ly significant systematic variations in P-det.Close and Q(max), indicates a physiological effect of repeated pressure-flow studies, resulting in a les s-obstructed second voiding. Supporting this, we found that all patients wh o changed group of classification of bladder outlet obstruction in the firs t examination shifted to a group of less obstruction, as did 66% of the pat ients who changed group of classification of bladder outlet obstruction in the second examination. Still, 80, respectively 85%, of the patients remain ed in the same group of classification of bladder outlet obstruction during retesting in the first and second examinations, respectively. Classifying the degree of bladder outlet obstruction by Q(max), P-det.Qmax, and P-det.C lose 85% of the patients reproduced their test results accurately in both e xaminations and taking only the first voiding in both examinations into acc ount 95% reproduced their test results. (C) 1999 Wiley-Liss, Inc.