Patients' lives could be put at risk by hospitals which use inaccurate weighing scales, the organisation which co-ordinates trading standards officers (Lacors) have said.
After pilot studies found hospital staff using inaccurate and unsuitable scales to calculate dosages of medication for patients, including small children, Lacors is launching a year-long crackdown.
Staff at one hospital were using ordinary bathroom scales to weigh a four-year-old cancer patient so they could work out how much radiation should be administered as part of her treatment.
The scales, which were unsuitable for use in a hospital, wrongly indicated that the girl had gained weight during the day despite not having eaten and suffering from suspected dehydration.
A spokesman for Lacors said the discrepancy could have led to the girl being given a potentially harmful dose of radiation treatment. During the pilot checks, inspectors also found weighing equipment was sometimes missing or staff did not have access to the correct scales for specific tasks.
The National Medical Weighing Project will start in April.
Trading standards officers from councils across the UK will work with their local NHS trusts to inspect all hospital weighing equipment and make sure it is accurate, legal and fit for purpose. Checks will particularly target oncology and paediatric departments.
Lacors chairman Geoffrey Theobald said: "Going into hospital for treatment can be a worrying time for many people, and it is important that patients have full confidence that they are being given the right dose of medicine or other treatments.
"The new National Medical Weighing Project will give patients the peace of mind that they are receiving the correct level of medication and will help hospitals iron out any problems involving the accuracy of their weighing equipment.
"It was clear from the pilot studies carried out that the accuracy of hospital scales is cause for concern. The new scheme will focus on making sure that hospital staff have the information and guidance they need to maintain the highest standards of accuracy. It is not about naming and shaming hospitals that are found to have problems, it is about working together to tackle a long standing problem."