The T zu C hi nomograms for maximum urinary flow rate ( Q max ) in children: comparison with M iskolc nomogram

Objective To report the first ranking method‐based age‐ and gender‐specific nomograms for maximum urinary flow rate ( Q max ) in children.Patients and Methods Healthy children aged 4–12 years were enrolled for two sets of uroflowmetry tests. The first and the higher value of the two consecutive Q max of each child with a voided volume ( VV ) of ≥50 mL were included for establishing single‐ and dual‐ Q max nomograms. Children with possible urinary tract infection or lower urinary tract dysfunctions were excluded.Results In all, 1128 children (583 boys and 545 girls) with a mean ( sd ) age of 7.7 (2.2) years were eligible for analysis and construction of nomograms. Multivariate analysis showed that the Q max was significantly affected by age, VV and gender (all P < 0.01). The values of the corresponding percentile of the Q max were significantly higher in the dual‐ Q max nomogram compared with the single‐nomogram. In boys aged 8–12 years, the 5th percentile line of the M iskolc nomogram was significantly lower than that of the present nomograms at all VVs . Minimally acceptable Q max values, around the 10th percentile of the dual‐ Q max nomogram, were >11.5 mL/s in children aged ≤6 years and >15.0 mL/s in children aged ≥7 years. External validation is required for the present dual‐ Q max nomograms.Conclusion We recommend repeating uroflowmetry in cases with a Q max lower than the minimally acceptable age‐ and gender‐specific Q max values.