Analysis of parental estimates of children's weights in the ED

Study objective: To assess the ability of parents to estimate their children's weight. Methods: We assembled a convenience sample of children, newborn to 5 years, who presented to the ED of a tertiary care hospital. Each child's mother or father was asked to estimate the child's weight as accurately as possible. The triage nurse then weighed the child on an electronic scale. An age-based formula was also used to estimate the child's weight. The parental estimate and the formula-based weight were compared with the weight indicated on the scale. Results: One hundred seventeen children were enrolled. The mean age was 26.7 months (range, newborn to 60 months). We analyzed agreement by plotting the percent difference between the weight estimates against the actual weights. The mean+/-SD difference between the parental estimate and the actual weight was 6.8%+/-9.8%. Parental estimates were accurate to within 10% of the measured weight in 80% of the cases (94 of 117). The mean+/-SD difference between the formula-derived weight and the actual weight was 13.6%+/-17.5%. The formula was accurate to within 10% of the measured weight in 46% of cases (54 of 117). Conclusion: In 80% of cases, the parental estimate of the child's weight was within 20% of the measured weight. The parental estimate was more accurate than the formula-derived weight.