What is the MUST malnutrition screening tool?

MUST (Malnutrition Universal Screening Tool) is a validated 3-item screening tool developed by BAPEN (British Association for Parenteral and Enteral Nutrition) in 2003. It assigns scores based on BMI, unintentional weight loss, and acute disease effect to classify adults as low, medium, or high risk for malnutrition. It takes 3–5 minutes and can be completed by any healthcare professional.

How do you calculate a MUST score?

Sum three scores: BMI score (>20 = 0, 18.5–20 = 1, 10% = 2) + acute disease effect (acutely ill and nil-by-mouth or likely to be for >5 days = 2; otherwise 0). Total score 0 = low risk, 1 = medium risk, ≥2 = high risk.

How is the MUST score interpreted?

MUST 0 = low risk: routine care, re-screen at agreed intervals (weekly in hospital, monthly in care home). MUST 1 = medium risk: observe, document intake, re-screen weekly (hospital) or monthly (care home). MUST ≥2 = high risk: refer to dietitian, initiate nutrition support, treat underlying cause of malnutrition.

What is the difference between MUST and NRS-2002?

MUST uses BMI, weight loss, and acute disease effect. It is community and hospital validated and the preferred tool in UK NHS settings (BAPEN). NRS-2002 adds a disease severity category and is recommended by ESPEN for hospitalized patients. Both have similar performance (sensitivity ~85%, specificity ~75%). The choice depends on setting and institutional guideline.

What is malnutrition risk in hospitals?

BAPEN national audits show that 25–34% of adult hospital admissions are at nutrition risk by MUST screening. Malnutrition is associated with longer hospital stays, higher complication rates, impaired immune function, poor wound healing, and increased mortality. Despite this, it is frequently under-recognized without systematic screening.

When should patients be referred to a dietitian?

A MUST score ≥2 requires dietitian referral — within 24–48 hours in most NHS hospital protocols. Medium-risk patients (MUST 1) may be monitored and referred if intake does not improve. Any patient with complex nutritional needs (swallowing difficulties, GI disease, malabsorption, renal failure, oncology) benefits from dietitian assessment regardless of MUST score.

What nutritional screening tools are available?

The main validated adult tools are: MUST (community and hospital; UK preferred), NRS-2002 (hospital; ESPEN preferred), MNA/MNA-SF (elderly; best for geriatric settings), and SGA (Subjective Global Assessment; reference standard for surgical patients). MUST is the most widely used in UK clinical practice.

What is the MUST score in hospitals?

In UK hospitals, MUST is recommended by NICE CG32 as the routine nutritional screening tool on admission. It is completed by nursing staff and documented as part of the admission assessment. High-risk patients (score ≥2) are flagged for dietitian review within 24–48 hours and have a nutrition care plan initiated.

What is the prevalence of malnutrition in hospitals?

Across UK and European hospitals, 25–34% of adult inpatients are at nutrition risk on admission. Prevalence is highest in elderly patients, oncology patients, those with GI disease, and major surgery patients. Hospital malnutrition prolongs inpatient stays by an average of 3–5 days and substantially increases healthcare costs.

How is malnutrition treated?

Treatment depends on cause and severity. First-line: oral nutritional supplements (ONS) to increase calorie and protein intake. If oral intake is insufficient: enteral nutrition via nasogastric or gastrostomy tube. If the GI tract is non-functional: parenteral nutrition (IV). Underlying causes (dysphagia, depression, nausea, poverty, dementia) must be addressed alongside nutritional supplementation.

What is the difference between enteral and parenteral nutrition?

Enteral nutrition delivers nutrients via the gut — either orally (supplements) or by tube feeding (nasogastric, PEG). Parenteral nutrition delivers nutrients directly into the bloodstream (IV), bypassing the gut. Enteral is always preferred when the GI tract is functional because it preserves gut integrity, is less expensive, and has lower infection risk. Parenteral is used only when enteral is impossible or insufficient.

Is MUST the same as the Mini Nutritional Assessment?

No. MUST and MNA (Mini Nutritional Assessment) are different tools. MUST is for all adults and uses BMI, weight loss, and acute disease. MNA/MNA-SF is specifically designed and validated for elderly patients (≥65) and includes functional status, cognitive factors, and dietary intake. MNA-SF is preferred in geriatric and care home settings.

Online Medical Tools — MUST Score

Printed on 9/3/2026

For informational purposes only. This is not medical advice.

Nutrition

MUST Score

The Malnutrition Universal Screening Tool (MUST) is a widely used adult nutrition screening framework that assigns points from three domains: BMI, unplanned weight loss, and acute disease with likely poor intake. The total score stratifies risk as low, medium, or high, helping trigger timely nutrition intervention.

Formula: MUST = BMI score (0-2) + weight-loss score (0-2) + acute disease effect score (0 or 2).

BMI score

Unplanned weight loss in past 3-6 months

Acute disease effect

Save your results with a free account

Keep a history of calculations, favorite tools, and access your dashboard anytime.

Create free account Sign in

How It Works

Score three clinical items

Assign a score to each of three domains: BMI (>20 = 0, 18.5–20 = 1, <18.5 = 2), unintentional weight loss in the past 3–6 months (<5% = 0, 5–10% = 1, >10% = 2), and acute disease effect (if the patient is acutely ill and has been, or is likely to be, nil by mouth for >5 days = 2).

Sum all three scores

Add the three scores together. The total ranges from 0 to 6. This sum is the MUST score and determines the level of malnutrition risk.

Act according to risk level

Score 0 = low risk (routine re-screening at intervals). Score 1 = medium risk (observe, document dietary intake, repeat screening in 1 week for hospital, 1 month for care home). Score ≥2 = high risk (refer to dietitian, initiate nutrition support, treat malnutrition).

Who Uses the MUST Score

Hospital Admission Nutritional Screening

Nurses, doctors & allied health teams

NICE CG32 mandates nutritional screening on admission for all adult hospital patients. MUST is the most widely used and validated tool for this purpose in the UK NHS. Screening takes only 3–5 minutes and identifies the 25–34% of admissions at nutrition risk.

Care Home Malnutrition Assessment

Care home staff & dietitians

MUST is validated for care home and community settings, not just hospitals. Residents should be screened on admission and monthly thereafter. Early identification allows targeted nutritional intervention before malnutrition becomes severe.

Community Dietitian Referral Decisions

Community nurses & GPs

In outpatient and community settings, MUST guides whether a patient needs dietitian referral. A score of ≥2 in the community should prompt GP review and/or dietitian assessment within an appropriate timeframe.

Pre-Operative Nutrition Optimization

Surgical teams & anesthesiologists

Malnutrition significantly increases surgical complications, infection risk, and length of stay. MUST screening before elective procedures identifies patients who may benefit from preoperative nutritional support (prehabilitation) to reduce operative risk.

Cancer Patient Nutritional Support

Oncology dietitians & clinical nurses

Cancer-related anorexia, weight loss, and treatment side effects frequently result in high MUST scores. Serial MUST monitoring throughout treatment enables timely nutritional intervention, which is associated with better treatment tolerance and quality of life.

Pro Tips

MUST takes only 3–5 minutes and is designed for all adults

Unlike complex nutrition assessments, MUST is designed for rapid use by any healthcare professional, not just dietitians. It requires no specialist training. All ward staff can complete it on admission.

If height and weight cannot be measured, use proxy measures

When direct measurement is impossible (e.g., bed-bound patients), estimate height from ulna length or knee height using validated conversion tables. MUAC (mid-upper arm circumference) can estimate BMI: MUAC <23.5 cm ≈ BMI <20; MUAC >32 cm ≈ BMI >30.

The acute disease effect item is frequently missed

Any acutely ill patient who is nil-by-mouth or at high risk of being unable to eat for >5 days scores 2 for the acute disease effect item — regardless of their BMI or weight loss. This is the most commonly omitted item in clinical practice.

NICE CG32 mandates screening on hospital admission

NICE Clinical Guideline CG32 (Nutrition Support for Adults, 2006) requires nutritional screening for all hospital inpatients using a validated tool such as MUST. This is a standard of care, not a recommendation.

High MUST (≥2) requires dietitian referral within 48 hours

Most NHS trusts specify that a MUST score ≥2 triggers a dietitian referral within 24–48 hours and initiation of a nutrition care plan. Always follow your institution's specific protocol.

Malnutrition affects 25–34% of all hospital admissions

BAPEN national audits consistently show that 25–34% of patients admitted to UK hospitals are at nutrition risk. Despite this prevalence, malnutrition is frequently under-recognized and undertreated without systematic screening.

MUST identifies risk — it does not assess specific deficiencies

A high MUST score indicates malnutrition risk based on anthropometrics and weight loss. It does not detect specific micronutrient deficiencies (iron, B12, folate, vitamin D) or assess the cause of malnutrition. Full dietitian assessment follows for positive screens.

Enteral nutrition is preferred over parenteral when the gut is functioning

When nutrition support is initiated following a high MUST score, enteral feeding (oral supplements, nasogastric, gastrostomy) is always preferred over parenteral nutrition when the GI tract is functioning. Enteral feeding preserves gut mucosal integrity and has lower infection risk.

MNA-SF is preferred in elderly/geriatric populations

The Mini Nutritional Assessment Short Form (MNA-SF) is specifically validated for elderly patients and includes functional and cognitive assessments that MUST does not. Consider MNA-SF for patients ≥65 years in geriatric settings.

NRS-2002 is preferred in hospital settings outside the UK

The Nutritional Risk Screening 2002 (NRS-2002) is more widely used in European hospital settings and includes a disease severity adjustment. ESPEN guidelines recommend NRS-2002 for hospitalized patients. MUST and NRS-2002 have similar sensitivity/specificity for detecting malnutrition.

Common Questions About Your Results

Both screen for malnutrition risk but differ in design. MUST uses BMI, weight loss, and acute disease effect — it is simple, community-validated, and widely used in UK NHS settings (BAPEN). NRS-2002 adds a disease severity adjustment and is recommended by ESPEN for European hospital settings. Both perform similarly for identifying malnutrition (sensitivity ~85%, specificity ~75%). Use the tool recommended by your institution.

Evidence-Based Methodology

MUST developed by BAPEN (Elia, 2003). Validated across hospital, care home, and community settings. Inter-rater reliability κ=0.88. NICE Clinical Guideline CG32 (2006) mandates universal nutritional screening on hospital admission. Sensitivity for malnutrition ~85%, specificity ~75% vs SGA reference standard. BAPEN 2011 audits: 25–34% of hospital admissions are at nutrition risk.

Clinical Content Trust

Last reviewed:: April 21, 2026
Guideline version:: General evidence framework v2026.04
Source set version:: Primary-source set v1

How to Interpret Your Result

A MUST score of 0 indicates low malnutrition risk and requires only routine re-screening at regular intervals. A score of 1 is medium risk and requires observation of dietary intake and repeat screening. A score of 2 or more indicates high risk, requiring referral to a dietitian, initiation of a nutrition care plan, and active treatment of malnutrition. In acutely ill patients, the acute disease effect item (which adds 2 points) ensures that any patient unable to eat for 5+ days is flagged as high risk regardless of their anthropometric status.

When to Use This Tool

Use MUST on admission for all adult hospital patients as required by NICE CG32, and at regular intervals thereafter (weekly in hospital, monthly in care home, annually in community settings). It is particularly important in high-risk populations: elderly patients, cancer patients, post-surgical patients, those with GI disease, and anyone with recent unintentional weight loss. Screen obese patients too — high BMI does not exclude malnutrition risk from weight loss or acute illness.

Limitations

MUST is a screening instrument only and does not replace full nutritional assessment by a registered dietitian. It does not identify specific nutritional deficiencies, quantify the degree of malnutrition, determine its etiology, or guide specific treatment. It also does not assess functional status, swallowing ability, or psychological factors affecting food intake — all of which are captured in more comprehensive assessment tools. In morbidly obese patients, the BMI component will always score 0, potentially underestimating risk if significant lean mass loss has occurred (sarcopenic obesity).

Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.

Changelog

April 21, 2026 · trust-baseline
Clinical trust metadata enabled for this tool page with structured review/version fields.

Related Tools