What is the primary purpose of the Malnutrition Universal Screening Tool?

November 19, 2025 •

4 min read

An estimated three million people in the UK are malnourished or at risk at any given time, highlighting the significant prevalence of this issue. The primary purpose of the Malnutrition Universal Screening Tool (MUST) is to efficiently and reliably identify adults who are malnourished, at risk of malnutrition, or obese across various healthcare settings.

Quick Summary

The Malnutrition Universal Screening Tool (MUST) is a widely used, five-step assessment for identifying adults at risk of malnutrition or obesity. It provides a standardized method for determining nutritional risk based on BMI, weight loss, and acute disease effects, which then directs appropriate management and care plans.

Key Points

Early Detection: The primary purpose is to quickly identify adults who are malnourished, at risk of undernutrition, or obese across various healthcare settings.
Standardized Process: MUST provides a simple, five-step, standardized method for nutritional screening, making it usable by any trained care worker.
Risk Assessment: The tool assesses three key indicators—Body Mass Index (BMI), unintentional weight loss, and the effect of acute disease—to calculate an overall risk score.
Tailored Management: The resulting risk score (low, medium, or high) directs specific, appropriate management guidelines, ranging from regular monitoring to dietician referral.
Improved Patient Outcomes: Implementing MUST and acting on its results can lead to better patient outcomes, including reduced complications, shorter hospital stays, and lower mortality rates.
Widespread Applicability: The tool is designed for universal use in hospitals, care homes, and community care, helping to ensure consistent screening practices.
Decision Support: MUST serves as a clinical decision support tool, helping practitioners initiate timely nutritional interventions and develop effective care plans.
Proactive Care: By focusing on early identification, MUST enables a proactive and preventive approach to counteracting malnutrition before it becomes severe.

The Core Objective of the Malnutrition Universal Screening Tool

The fundamental objective of the Malnutrition Universal Screening Tool (MUST), developed by the British Association for Parenteral and Enteral Nutrition (BAPEN), is to serve as a practical, standardized, and easy-to-use method for identifying adults at risk of disease-related malnutrition. This encompasses identifying those who are already malnourished, at risk of undernutrition, or obese. The universal nature of the tool means it is applicable across all adult care settings, including hospitals, care homes, and community-based healthcare. By providing a systematic approach, MUST ensures that malnutrition, a condition often under-diagnosed despite its high prevalence and adverse effects, is consistently detected and addressed early. Early identification is crucial, as timely nutritional intervention can significantly improve patient outcomes, reduce complication rates, and lower overall healthcare costs.

The Five Steps of the MUST Assessment

To achieve its purpose, MUST follows a simple, five-step process that any trained care worker can implement.

Measure BMI Score: The first step involves calculating the patient's Body Mass Index (BMI) using their height and weight. This provides a baseline measure of their current weight status, with a low BMI indicating an initial risk factor for malnutrition.
Note Weight Loss Score: The second step assesses the percentage of unintentional weight loss over the last 3-6 months. Significant unplanned weight loss is a critical indicator of deteriorating nutritional status and contributes to the overall risk score.
Establish Acute Disease Effect Score: This step determines if the patient's acute illness or condition has led to a lack of nutritional intake for five days or more. Conditions like critical illness, gastrointestinal surgery, or severe swallowing difficulties are considered.
Determine Overall Risk Score: The scores from the first three steps are added together. A total score of 0 indicates low risk, 1 signifies medium risk, and 2 or more indicates a high risk of malnutrition.
Develop Management Guidelines: Based on the final risk score, healthcare professionals are guided toward appropriate management actions and the development of a care plan.

Comparison of MUST with Other Tools

While MUST is a highly effective and widely used screening tool, other nutritional assessment methods exist, each with a different focus. The Patient-Generated Subjective Global Assessment Short Form (PG-SGA SF) is another recognized tool, often providing a more detailed evaluation by considering factors like recent food intake and nutritional impact symptoms, in addition to weight history.


Feature	Malnutrition Universal Screening Tool (MUST)	Patient-Generated Subjective Global Assessment (PG-SGA SF)
Purpose	Quick, universal screening to identify adults at risk of malnutrition or obesity.	More detailed assessment, including risk factors for developing malnutrition, often used after initial screening.
Parameters	BMI, unintentional weight loss, acute disease effect.	Weight history, food intake, nutritional impact symptoms, functional status.
Application	Broadly applicable across all care settings, for any trained staff.	Suitable for self-completion by patients with support, or for detailed follow-up.
Focus	Identifies characteristics of existing malnutrition or risk.	Identifies characteristics and risk factors for future development.
Duration	Quick and simple to use.	Slightly more complex and time-consuming.

Conclusion

The primary purpose of the Malnutrition Universal Screening Tool is to provide healthcare professionals with a simple, effective, and standardized method for the early identification of nutritional risk in adult patients. By systematically evaluating BMI, recent weight loss, and the impact of acute illness, the tool helps categorize risk levels and directs subsequent management actions, from monitoring dietary intake to specialized dietician referral. This proactive approach is fundamental to mitigating the serious health consequences of malnutrition, such as increased complications, longer hospital stays, and higher mortality rates. While screening tools like MUST should always be used alongside clinical judgment, their widespread use has proven to be an invaluable component of effective patient care. For more detailed information on the tool and its use, see the resources provided by the British Association for Parenteral and Enteral Nutrition (BAPEN).

Note: While MUST is highly effective, it does not screen for deficiencies in vitamins or minerals.

Addressing the High-Risk Score

For patients identified as high risk by MUST, the management plan typically involves more intensive nutritional support. This often includes a referral to a dietitian or nutritional support team for a more comprehensive dietary assessment and the creation of a personalized care plan. Interventions may involve oral nutritional supplements, food fortification, or, in severe cases, enteral or parenteral nutrition. Regular monitoring is essential to track progress and ensure the patient's nutritional status improves over time.

Malnutrition and Patient Recovery

Malnutrition is both a cause and an effect of ill health. For example, a patient recovering from surgery or a severe illness may have a poor appetite and increased nutritional needs, leading to malnutrition. This, in turn, can hinder recovery, weaken the immune system, and increase the risk of complications. By utilizing MUST to promptly identify and treat nutritional risk, healthcare teams can break this vicious cycle, supporting the patient's recovery and rehabilitation. Regular nutritional screening is a fundamental part of providing comprehensive, patient-centered care.

Frequently Asked Questions

The primary purpose of the Malnutrition Universal Screening Tool (MUST) is to identify adults who are malnourished, at risk of malnutrition, or obese, and to provide a standardized approach for their subsequent care and management.

The five steps are: 1) Measure BMI score, 2) Note percentage unplanned weight loss, 3) Establish acute disease effect score, 4) Determine the overall risk score, and 5) Use management guidelines to create a care plan.

MUST was developed by the British Association for Parenteral and Enteral Nutrition (BAPEN) in the early 2000s to create a reliable and easy-to-use screening tool.

The frequency of re-screening depends on the patient's risk and setting: weekly in hospitals, monthly in care homes, and annually for specific risk groups in the community.

If a patient is at high risk, they should be referred to a dietitian or nutritional support team for a more detailed assessment and to begin nutritional support therapy following local policy.

No, MUST has not been designed for and is not suitable for use with children. It is specifically intended for adults.

MUST is not designed to detect deficiencies or excessive intakes of specific vitamins and minerals. While it is a good general screening tool, it does not replace the need for full clinical judgment.

Screening, such as using MUST, is a quick process to identify individuals at risk. Assessment is a more detailed, in-depth evaluation performed by a specialist, like a dietitian, for those identified as being at risk.