title: Finger counting method is more accurate than age-based weight estimation formulae in estimating the weight of Hong Kong children presenting to the emergency department.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the finger counting method and compare its performance with four commonly used age-based weight estimation formulae in children aged 1-9 years presenting to the ED in Hong Kong.
  
  
  METHODS
  A cross-sectional, observational study of children aged 1-9 years who presented to the ED of a tertiary referral hospital in Hong Kong over a 6 month period was conducted. Actual weight was compared with estimated weight using the finger counting method and four commonly used age-based weight estimation formulae. Bland-Altman analysis was performed to evaluate the degree of agreement in which the mean percentage difference (MPD) and 95% limits of agreement (LOA) were calculated. Root mean squared error (RMSE) and proportions of weight estimates within 10%, 15% and 20% of actual weight were determined.
  
  
  RESULTS
  A total of 4178 children were included. The finger counting method was the most accurate method (MPD 0.1%; 95% LOA -34.0% to 34.2%). The original Advanced Paediatric Life Support (APLS) formula (MPD -7.0%; 95% LOA -38.4% to 24.3%) and the updated APLS formula (MPD -0.4%; 95% LOA -38.5% to 37.8%) underestimated weight whereas the Luscombe formula (MPD 7.2%; 95% LOA -31.8% to 46.2%) and the Best Guess formula (MPD 10.6%; 95% LOA -27.3% to 48.4%) overestimated weight. The finger counting method had smallest RMSE of 4.06 kg and estimated the largest proportion of children within 10%, 15% and 20% of actual weight.
  
  
  CONCLUSIONS
  The finger counting method outperforms the commonly used age-based weight estimation formulae in children aged 1-9 years presenting to the ED in Hong Kong.
authors.affiliation: Accident and Emergency Department, Princess Margaret Hospital, Kowloon, Hong Kong.
authors.forename: Jerome Lt
authors.initials: JL
authors.lastname: So
authors.affiliation: Central Clinical School, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia.
authors.forename: Eric Pf
authors.initials: EP
authors.lastname: Chow
authors.affiliation: Emergency Department, Princess Royal University Hospital, London, UK.
authors.forename: Giles N
authors.initials: GN
authors.lastname: Cattermole
authors.affiliation: Accident and Emergency Medicine Academic Unit, Chinese University of Hong Kong, Hong Kong.
authors.forename: Colin A
authors.initials: CA
authors.lastname: Graham
authors.affiliation: Accident and Emergency Medicine Academic Unit, Chinese University of Hong Kong, Hong Kong.|Emergency Medicine Academic Unit, Cardiff University, Wales, UK.
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Rainer
mesh_terms: D000886:Anthropometry / Q000379:methods*; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004636:Emergency Service, Hospital; D005260:Female; D005385:Fingers; D006723:Hong Kong; D006801:Humans; D007223:Infant; D008297:Male; D010372:Pediatrics / Q000379:methods*; D012189:Retrospective Studies
keywords: Dimensional Measurement Accuracy; Hong Kong; bodyweights and measures; child; infant; preschool