Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Changing practice

Auditing the nursing standard for weighing patients on an acute medical unit

  • Comment

An audit of admission observations identified that patients were not always weighed and that the standard for observations was not appropriate


Liz Lees, MSc, BSc, DipN, DipHSM, RGN, is consultant nurse; Gaynor Allen-Mills, RGN, is senior sister, both at Heart of England NHS Foundation Trust, Birmingham.



Lees, L., Allen-Mills, G. (2009) Auditing the nursing standard for weighing patients on an acute medical unit. Nursing Times; 105: 27, early online publication.

This article describes an audit of a standard for observations and assessments introduced on an acute medical unit (AMU), one element of which was patient weight. It revealed that only 50% of nurses routinely weighed patients as part of the admission process and/or as part of nutritional screening. Revisions were made to the existing nursing standard.

Keywords: Nutrition screening, Weight, assessment, Documentation

  • This article has been double-blind peer-reviewed



  • A nursing standard outlining the components required for a patient assessment and frequency of observations on the AMU was introduced at the Heart of England NHS Foundation Trust in January 2008.
  • It was decided that the standards for patients attending the assessment area and admission area should be different, and were based on clinical urgency, recommendations of clinical protocols, the route of admission and time spent in the unit (Chellel, 2002).
  • For example, when patients are referred via their GP, nurses conduct a full set of observations and only relevant risk assessments according to the patient’s presenting problems and condition on arrival (Royal College of Physicians, 2007) (Box 1).

Acute medical unit

The acute medical unit at Heartlands hospital has an assessment area and an admissions area. Patients in the assessment area may not be admitted to hospital while those in the admission area are admitted for up to 48 hours before being transferred to another ward or discharged home. Patients attending the unit are:

  • Referred by their GP (requiring full initial assessment);
  • Admitted from A&E (requiring reassessment).

When patients are referred from A&E, all initial systemic observations are reassessed immediately or within 30 minutes, depending on their Modified Early Warning System score (MEWS). The aim is to maintain patient safety through high-quality care and appropriate treatments commenced in a timely manner (Chellel, 2002). However, there was consistently poor compliance with the standard for weighing patients (Sylvain, 2009), which stated that: ‘all patients should be weighed, including those presenting for assessment or being admitted to the acute medical unit’.

Nurses questioned whether it was appropriate to weigh all patients who attended the AMU for assessment when some may not be admitted to hospital or have only a short stay.

The audit

Thirty band 5 and 6 nurses participated in an audit of practice on the AMU. Band 7 nurses and the matron were excluded as they had participated in developing the standard for observations and assessments. Five questions explored why patients were or were not weighed:

  1. Do you weigh all patients as part of the admission process?
  2. Should all patients presenting and subsequently admitted to AMU be weighed?
  3. What are the reasons for weighing patients on the assessment area of the AMU?
  4. Is the trust nutritional screening assessment completed on admission?
  5. To what extent is the trust nutritional screening assessment effective in its current form?


Twenty nurses said they always weighed patients as part of the admission process. When asked if they thought patients should be routinely weighed, 15 nurses said ‘yes’ and 15 responded ‘no’.

When asked why they weighed patients, nurses could give as many reasons as they wanted (Fig 1). The most popular was because the patient was taking medications. Enoxaparin was the most commonly cited medication, as the dose is calculated according to the patient’s weight.

Little importance was placed on whether patients looked thin, obese or frail. Anecdotal evidence suggested that nurses did not feel this should influence the decision whether or not to weigh patients. Nurses frequently expressed a reluctance to weigh patients stating that it was potentially invasive if they did not have a good reason to do so. Band 6 nurses identified more reasons why they weighed patients and were also more specific about medications where weight was important.

Of 34 nutrition screening tools audited, 100% were completed on admission yet the audit suggests the recommended actions arising from this screening – such as triggers to weigh a patient – were not always carried out.

When we looked at the effectiveness of the trust’s nutrition screening tool we found that two patients had food charts to record whether or not they were eating adequately and had been identified as being at moderate risk of malnutrition. They should have been weighed but this had not been recorded at 48 or 72 hours following admission.

Two patients had moderate risk identified and it was noted that they had lost weight but they had not been weighed since admission. In one case the patient had been on the AMU for three days.

The patient perspectives

When we asked patients if they had been weighed since admission, only two out of 34 had been. Five had been asked to estimate their weight and this figure had been recorded, but not as an estimated weight. This is unacceptable practice as patients often underestimate by up to 10% (Menon and Kelly, 2005).

Patient accounts were corroborated with evidence from charts at the end of their bed, treatment sheets and medical notes. Patient narratives suggested that junior doctors tended to ask for estimations of weight when prescribing diuretics and enoxaparin (Sylvain, 2009). Two patients agreed to be weighed to assess whether their estimated weight was accurate:

  • Patient 1: estimated 72kg, actual 81kg;
  • Patient 2: estimated 65kg, actual 60kg.

The doctors said they did not always ask for nurses to be weighed as they felt nurses were too busy (Hilmer et al, 2007). However, nurses stated that they were often prevented from weighing patients due to insufficient or inappropriate equipment (Sylvain, 2009). This was investigated and three sets of scales were purchased. Nurses were also reminded that equipment for weighing immobile patients and those confined to bed is available from the hospital’s equipment resources centre.

Key findings

  • The standard that all patients should be weighed was not appropriate to the AMU and a different approach was needed for those requiring assessment and those requiring admission.
  • The conducting of nutritional screening assessments received 100% compliance but findings were not acted on.
  • Only two patients had their weight recorded, and this was when a clearly identified risk was demonstrated. Other high-risk and moderate-risk patients were missed.
  • Junior doctors were asking patients to guess their weight when prescribing medicines.
  • Insufficient equipment to weigh patients was available on the AMU.
  • Senior nurses used their experience to state multiple reasons why patients should be weighed but band 5 nurses appeared to have less knowledge.


Nurses seem reluctant to weigh patients routinely as part of the admission process. It appears that the nutritional assessment tool is the preferred trigger for weight assessment as it provides a standardised rationale (DH, 2007). If this tool is to be relied on then the actions it triggers must be carried out (NICE, 2006).

The recommended standard for assessment and admission processes would be to weigh all patients on assessment or admission to hospital so that vulnerable patients are not missed. A more pragmatic viewpoint is ‘weigh for a purpose’ (DH, 2007), where patients are weighed only if it is relevant to their treatment. This seems more appropriate given the high volume of patients admitted through an AMU and that not all patients need to be weighed on admission.

Conversely, it could be argued that when medicolegal issues are raised about malnutrition and associated weight loss the only defence would be to have weighed the patient on admission (as a baseline) and weekly thereafter (Hilmer et al, 2007; NICE, 2006).

Finally, when patients are transferred to another ward if they need a hospital stay over 48 hours, there is a risk that they may not be weighed on the admitting ward.

Changing practice

Weighing patients used to be a standard part of an admission process. We found that in an AMU nurses do not attach the same importance to weighing patients as to other assessments. This may be reasonable given the number of investigations and assessments undertaken in the first 24 hours after admission. Prioritising workload is crucial to the efficient running of an AMU - we believe healthcare assistants can contribute to the admission process and weigh patients but are not always empowered to do this.

The AMU nursing team are 100% compliant with completing the trust’s nutritional screening tool but not compliant in following through actions that would complete the process. This means compliance with nutritional risk assessments alone cannot assure the elimination of risks. We also found that the attitude of the doctor or nurse to recording weight directly influences whether this observation is completed.

The solution is to provide a definitive list of reasons to weigh patients in the assessment area. The list would promote the idea of weighing for purpose and include issues related to:

  • Prescribing medicines;
  • Tissue viability;
  • Manual handling.

We have separated the nursing standard for assessment and observations into two parts to reflect the differences in patients attending the AMU for assessment and admission. Those in the assessment area are now weighed for a purpose identified on the list and weighed according to their nutritional risk score in the admissions area.


This work has proved invaluable in exploring the issues underpinning nurses’reluctance to weigh patients and the use of risk assessments that seem to have replaced individual judgement over when to weigh or not to weigh patients. When the new standard is embedded a re-audit will indicate whether the new process is more effective.


Practice points

  • Patients on AMUs should be weighed when it is relevant to their treatment or in response to triggers from a nutrition assessment.
  • Patients’ weight should not be estimated as it will not be accurate.
  • Appropriate equipment should be available to weigh patients who are immobile or confined to bed.


  • Comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Links may be included in your comments but HTML is not permitted.