Evaluation of the Mercy TAPE: Performance against the standard for pediatric weight estimation

Study objective: We assessed the performance of 2 new devices (2D- and 3D-Mercy TAPE) to implement the Mercy Method for pediatric weight estimation and contrasted their accuracy with the Broselow method. Methods: We enrolled children aged 2 months through 16 years in this prospective, multicenter, observational study. Height/length, weight, humeral length, and mid-upper arm circumference were obtained for each child, using calibrated scales and measures. We then made measurements with blinded versions of the 2D- and 3D-TAPEs. Using height/length data, we calculated the weight estimated by the Broselow method. We contrasted measures with mean error, mean percentage error, and percentage predicted within 10% and 20% of actual. Results: Six hundred twenty-four participants (median 8.5 years, 27.6 kg, 17.3 kg/m²) completed the study. Mean error was 0.3 kg (mean percentage error 1.6%), 0.2 kg (mean percentage error 1.9%), and -1.3 kg (mean percentage error -4.1%) for 2D-, 3D-, and Broselow, respectively. Concordance between both TAPE devices and the Mercy Method was greater than 0.99. The proportion of children predicted within 10% and 20% of actual weight was 76% and 98% for the 2D-TAPE and 65% and 93% for the 3D-TAPE. Excluding the 209 (33%) children who were too tall for the device, Broselow predictions were within 10% and 20% of actual weight in 59% and 91%. Conclusion: The 2D- and 3D-Mercy TAPEs outperform the Broselow tape for pediatric weight estimation and can be used in a wider range of children.