Validation of age-based body mass estimation methods in toddlers and pre-school children


  • Karin Booysen
  • Johannes Marthinus Dippenaar University of Pretoria
  • Francois Jacobus Smith University of Pretoria


anaesthesia, anthropometric, bodyweight, children, mass, paediatric, South Africa


Background: Body mass is commonly used to determine medication dosages and equipment size. In emergency situations (including cases necessitating surgery) weighing paediatric patients can be impractical. Clinicians may use any of several body mass estimation techniques to surmount this obstacle. This study’s aim was to compare the actual body mass of children with estimated mass as predicted by several commonly used estimation methods.

Methods: This diagnostic cross-sectional study recorded data from patients between one and five years of age in the Tshwane district. Measurement procedures were standardised to ensure consistency. 

Results: The relationship between anthropometric and demographic variables were determined and applied to different estimation models to assess the models’ applicability to the Tshwane district population. The APLS (Advanced Paediatric Life Support) formula (Body mass (kg) = (Age + 4) × 2) proved the most appropriate. This formula gave a mean  underestimation of 0.51 kg. Age proved to be the variable with the strongest correlation to body mass. A formula was developed specifically for the selected population, adding mid upper arm circumference as a second variable. This formula is more complex and offers only a marginal improvement in accuracy of weight estimation.

Conclusion: The APLS formula is a reasonable tool to use when estimating the body mass in children between one and five years old in the Tshwane district population. It is a well-known and simple formula, making it well suited to this purpose.

Author Biographies

Karin Booysen

Private Practice, Pretoria, South Africa

Johannes Marthinus Dippenaar, University of Pretoria

Department of Maxillo-Oral-Facial Surgery, Oral Health Centre, University of Pretoria, Pretoria, South Africa

Francois Jacobus Smith, University of Pretoria

Department of Anaesthesiology, University of Pretoria, Pretoria, South Africa






Research Articles