MUST: The Malnutrition Universal Screening Tool Explained

Malnutrition in older adults is often quietly progressive — a bit less eaten here, a slightly looser waistband there — and by the time it's obvious to the eye, a resident may already have lost significant strength, resilience, and ability to recover from illness or injury. The Malnutrition Universal Screening Tool, known as MUST, exists to catch this decline early with a structured, consistent process, rather than relying on staff noticing a change that's often gradual enough to miss.

What MUST Is and Where It Came From

MUST was developed by the Malnutrition Advisory Group, a standing committee of BAPEN (the British Association for Parenteral and Enteral Nutrition), and is backed by major UK healthcare bodies including the British Dietetic Association and the Royal College of Nursing. It's now the most widely used nutritional screening tool in the UK, applied consistently across hospitals, primary care, and care homes, which makes it a genuinely standard, well-understood tool for staff moving between different care settings.

How the Tool Works

MUST combines a few simple measurements into an overall malnutrition risk score: current body mass index, percentage of unplanned weight loss over recent months, and the likely effect of acute illness — for example, whether the resident has had, or is likely to have, no nutritional intake for an extended period due to illness. These combine into a score that classifies a resident as low, medium, or high risk of malnutrition, with a corresponding recommended action for each risk band, from routine monitoring at the low end through to a dietitian referral and structured nutritional support plan at the higher end.

Why Screening Regularly Matters

A one-off MUST assessment at admission captures a snapshot, but nutritional risk changes — sometimes quickly, following illness, a change in mobility that affects someone's ability to prepare or reach food, dental problems, or low mood affecting appetite. Regular rescreening, at intervals set by the service's policy and always after any acute illness or significant change, catches this drift before it becomes a serious problem. This mirrors the same principle behind the Waterlow pressure ulcer risk score — a risk tool only protects someone if it's genuinely kept current, not filed away after a single admission assessment.

Practical Barriers to Accurate Screening

Getting an accurate MUST score in practice isn't always straightforward. Weighing a resident who has limited mobility or uses a wheelchair may need specific equipment or technique, and height can be difficult to measure directly in someone unable to stand — alternative measurements exist for these situations, and staff should know them rather than skipping the step or estimating. Staff should also be alert to factors that can distort the picture on a single occasion, such as fluid retention affecting weight, or recent illness affecting how representative a single weigh-in is of someone's underlying nutritional trend. Consistent technique and equipment, used the same way by whoever is carrying out the assessment, make scores far more meaningful and comparable over time than one-off measurements taken inconsistently by different staff using different methods.

Turning a MUST Score Into Action

A medium or high MUST score should trigger specific, documented actions — not just a note in the file. This might include food charts to track actual intake accurately rather than relying on impressions, fortified food or nutritional supplements where appropriate, more frequent small meals and snacks rather than relying solely on three larger meals, and referral to a dietitian for residents at higher risk. Staff should understand why these actions matter clinically, not just follow them as a checklist, since genuine understanding makes it far more likely that food charts get filled in accurately and consistently rather than treated as an administrative afterthought.

Connecting MUST to Wider Nutrition and Hydration Care

MUST screening sits within a much broader picture of nutritional wellbeing that includes hydration, mealtime support, and dignified eating environments, covered more fully in nutrition and hydration compliance training. A structured screening tool identifies who needs closer attention; the day-to-day practice of supporting someone to actually eat and drink well is what turns that identification into a genuinely better outcome.

Frequently Asked Questions

How often should MUST screening be repeated?
At intervals set by the service's policy, and always following any acute illness, hospital admission, or significant change in a resident's condition.

Does a low MUST score mean nutrition doesn't need attention?
A low score means low risk based on current information, not that nutrition can be ignored — ongoing monitoring and good mealtime support still matter for every resident.

Who should complete a MUST assessment?
Trained care or nursing staff can complete the screening as part of routine care; higher-risk results should prompt referral to a dietitian or appropriate clinician for a fuller nutritional assessment.

Early, structured nutritional screening protects strength, resilience, and recovery. Learnsignal's CPD courses for care and healthcare staff cover MUST and other risk assessment tools alongside the wider nutrition curriculum.