Introduction:
The child's body weight is very important in the proper pharmacotherapy in emergency situations.

Aim:
The aim of the study is to assess the reliability of information on the current body weight of a pediatric patient obtained by taking history in emergencies. Additionally, the effectiveness of commonly used age-dependent weight formulas for children was analysed.

Material and methods:
The study was retrospective. We have collected 1103 cases of pediatric patients admitted to the Emergency Department in the second half of 2018, in whom data on body weight were obtained by history taking and by weighing the patient. Subsequently, based on the patient’s age, their weight was estimated using 13 different formulas.

Results and discussion:
Parents, caregivers or teenagers are reliable sources of information about the patient’s actual weight. In 86% of cases the data from the medical history were within the range defined as acceptable (±10% in comparison with the actual body weight). Underestimating body weight was a more frequent mistake than its overestimation. None of the formulas gave half as accurate results as medical history data. Of all the formulas, the best results were reported for the Park formula, however, only 42% of the estimates were within the acceptable range.

Conclusions:
Weight information obtained from children and their parents or caregivers is more reliable in terms of determining the child’s actual body weight than any formula for body weight estimation. If it is necessary to use any of the formulas for approximate body weight, it is most preferable to use the Park formula.