Following recent reports in the national press over inaccurate hospital weighing scales that could be putting patients’ lives at risk, LACORS (Local Authority Coordinators of Regulatory Services) has launched a project to improve standards and practices in NHS trusts across the UK.

Called the National Medical Weighing Project, the scheme is designed to identify the problems, recommend solutions and work with staff to improve standards across every NHS trust in the UK. And, from April this year, trading standards officers begin the task of inspecting the patient weighing scales in use in hospitals to make sure that they are accurate, legal and fit for purpose.

In this brief guide, John Stokes, Senior Direct Sales Officer from Avery Weigh-Tronix, the largest supplier of patient weighing equipment in the UK will explain the current medical weighing regulations that all healthcare professionals need to understand and act upon and offer practical advice on the best ways to achieve compliance.

The right scale for task
On 1st January 2003, the Non-Automatic Weighing Instruments (NAWI) Directive became law meaning that from this date, all new weighing instruments used for medical weighing purposes have to comply with the standard. One recommendation of this standard is that any weighing scale purchased must meet the minimum instrument classification for the application – in other words, it must be fit for its purpose.

On paper the classifications may appear confusing and suggests Stokes, this can leave healthcare professionals unsure about which scale to use for the application or at worse, unaware of the consequences of choosing equipment that is not sufficiently accurate.

The good news, says Stokes is that in practice the classification system is simple with only two levels of classification that apply to patient weighing equipment, making it easier for the trust’s procurement department to make an informed decision on which type of equipment to purchase.

Class III scales are needed for critical applications, such as calculating the precise radiation dosage for cancer patients or for determining medication levels for babies in an intensive care unit. Here, the scales’ resolution – the divisions between weight readings- is of prime importance, with the smallest intervals of around 5 grams giving the highest accuracy.

Class IIII scales are appropriate when the patient is being weighed to monitor his or her general health rather than to determine dosage and will weigh in intervals of around 20 grams. There is also a third classification called Class II, although this applies to highly-sensitive laboratory weighing scales with smaller divisions and is not included in the trading standards assessment.

If there is any doubt, the safest option, suggests Stokes is to choose a Class III scale every time. This will always provide the highest levels of accuracy for any patient weighing application and will ensure that the trust meets its duty of care obligations and can prove due diligence in the event of any litigation.

Stamping out errors
The NAWI Directive also stipulates that all patient weighing equipment purchased from 1st January 2003 must be properly verified, so as well as choosing the correct specification of scale, it is equally important to ensure that your scale is correctly stamped and therefore legally approved for use. This will help you to avoid instances of unsuitable equipment being purchased in error or of inadequate donated scales, such as domestic kitchen or bathroom scales being used.

To further help you to make the right decision and keep your equipment operating accurately, it is also important to understand the differences between stamping/verification, calibration and checkweighing.

Avery Weigh-Tronix recommends that staff carry out routine checkweighing on all patient weighing equipment at least once a week on frequently-used machines, by using certified weights to check that the scale is weighing consistently through its capacity.

In addition, each scale should be maintained routinely and calibrated at least once every 12 months by a qualified engineer, who can service and adjust the scale and provide a calibration certificate as proof that the scale is operating accurately.

However, if the scale requires repair work that would effectively break the original seal, such as the replacement of a load cell or PCB board, then it must be restamped, either by a verified technician on site or by returning it to the equipment manufacturer.

As the country’s leading supplier of patient weighing equipment, Avery Weigh-Tronix has many years’ experience of working with NHS Trusts and can advise you on all your weighing concerns – from purchasing the correct equipment, to professional service including preventative maintenance, repair and calibration to complete asset management solutions to identify and monitor all patient weighing equipment held by the Trust.

For further information, please contact Avery Weigh-Tronix on 0845 3 66 77 88.