Guess the weight: the accuracy of estimated weight for surgical admissions - a comparison study

An accurate body weight is vital for safe dosing of many drugs. Weight is often unavailable for emergency admissions and an estimation is used. Emergency Department staff are poor at estimating patient weight, but no data existed for surgical admissions. This study assesses the reliability of weight estimation by patients and healthcare workers.

All emergency surgical patients admitted during one week were approached. If consented, four healthcare workers (consultant, foundation doctor, nurse, support worker) independently estimated their weight. The patients then gave their estimate. Actual weight was measured and data analysed. Seventy-two consecutive surgical admissions were included, aged 16-95 and 52% male. Healthcare workers correctly (within ±10% margin) estimated the weight for only 57% of patients. Further statistical analysis confirmed that staff are inaccurate estimators and patients are better at estimating their own weight (p < 0.006).

Staff are poor at estimating weight and the study was unable to show statistical superiority of any professional group when guessing weights. There was also a tendency for staff to increasingly under-estimate as weight increases. Patients are the most accurate estimators, but self-reporting is still too unreliable for drug dosing and should stop.