A two-day bladder diary for children: Is it enough?

When using the 2-day diary, a 16% false negative rate for frequency should be expected. A 2-day bladder diary is sufficient to evaluate bladder capacity and fluid intake.Table. Comparison of 2-day and 3-day voiding diaries for the number of voids and low bladder capacity.2-day voiding diary3-day voiding diaryHigher number of voids (≥8 voids/day)Low bladder capacity (<65% of the expected bladder capacity)YesNoTotalYesNoTotalYes20 (83.4%)5 (8.3%)2570 (97.2%)1 (9.1%)71No4 (16.6%)55 (91.7%)592 (2.8%)10 (90.9%)12Total246084721183*Sample of 92 children. Missing value for number of voids, eight (8.7%); for bladder capacity, nine (9.7%).