Evaluation of the accuracy of different methods used to estimate weights in the pediatric population

The purpose of this study was to compare the predictive accuracy of 3 methods (Broselow tape, Leffler formula, and Theron formula) for pediatric weight estimation to identify factors that can influence weight estimation, and to derive alternative models for such estimation if indicated.

This was a prospective, nonblinded observational study. Every patient in the cohort was < or =10 years of age. The patients' age and height were used to estimate their weight by using the 3 previously mentioned methods. These estimated weights were compared with the patients' actual weight by using the modified Bland-Altman method.

One thousand eleven subjects were included. Percent differences between predicted and actual weight were significantly less using the Broselow tape compared with other methods for patients weighing <10 or 10 to 25 kg and for the Theron formula compared with other methods for patients weighing >40 kg. For patients weighing 25.1 to 40 kg, performance of the Broselow tape and Leffler method were similar, and both were superior to the Theron formula. Three weight predictors (age, gender, and ethnicity) were identified, and 2 new weight-estimation models were derived from the cohort.

The Broselow tape is accurate for weight estimation in children < or =25 kg, but the Theron formula performs better with patients weighing >40 kg. The Broselow tape was not statistically superior to the Leffler formula in subjects weighing 25.1 to 40 kg. A separate cohort is needed to evaluate the validity of the alternative predictive formulae.