“…In the interpretable pressure-flow traces, Q max , urethral resistance (OCO), grading and classifying of obstruction underwent significant systematic changes; P det.Qmax had no systematically significant changes, but with considerable intra-individual changes after manual correction. Q max reduced consistently by 1.17 ml/ sec on average, which was similar to the result (by 1.5 ml/ sec on average) reported by Grino et al in 1645 uroflow measurements and the result (by 0.8 ml/ sec on average) reported by Madsen et al in pressure-flow studies of 25 patients (Grino et al 1993;Madsen et al 1995). In this study, 81.8% traces showed obvious artifacts of Q max .…”