What MST score indicates malnutrition risk?

A total score of 2 or more indicates elevated malnutrition risk. Scores of 0–1 are generally considered not at risk, though clinical judgment should always supplement screening results.

How long does MST take to administer?

MST typically takes under one minute. It consists of two weighted questions about recent unintentional weight loss and reduced appetite, requiring no laboratory values or physical measurements.

What is the sensitivity and specificity of MST?

MST has a reported sensitivity of approximately 93% and specificity of 93% for identifying malnutrition risk in hospitalized patients, making it one of the most accurate brief screening tools available.

Who developed and validated MST?

MST was developed by Ferguson and colleagues and validated in adult acute hospital patients. It is endorsed by the Academy of Nutrition and Dietetics (AND) as a valid and reliable malnutrition screen.

Does MST require BMI or laboratory values?

No. MST relies entirely on patient-reported history of weight loss and appetite reduction. This makes it practical for settings where objective measurements are not immediately available.

In which patient populations is MST validated?

MST is validated in general hospital inpatients, oncology patients, elderly patients, and ambulatory settings. It has broad applicability across adult clinical populations.

What action should a positive MST score trigger?

A positive MST screen (score ≥2) should trigger a formal nutrition assessment by a dietitian, initiation of a nutrition care plan, and monitoring of dietary intake. The specific pathway depends on institutional protocol.

How is the MST scored?

The weight loss item is weighted 0–4 based on amount lost; the appetite item scores 0 or 1. The two are summed for a total of 0–5. A higher score reflects greater malnutrition risk.

Can MST detect risk before visible malnutrition develops?

Yes. The appetite item captures early anorexia that may precede measurable weight loss, allowing intervention before significant nutritional depletion occurs.

How does MST compare to the MUST score?

MST is shorter (2 items) and does not include BMI or a disease-effect score. MUST provides a more detailed risk stratification but requires additional measurements. MST is preferable when speed is critical.

Should MST be repeated during a hospital stay?

Yes. Weekly rescreening is commonly recommended for patients with prolonged admissions or changing clinical status. Nutritional risk can change significantly over the course of an illness.

Is MST appropriate for patients who cannot self-report?

When patients cannot self-report (due to cognitive impairment, delirium, or critical illness), proxy informant responses from carers or family members may be used, or an alternative observational tool such as MUST may be more appropriate.

Online Medical Tools — MST Score

Printed on 9/4/2026

For informational purposes only. This is not medical advice.

Geriatrics

MST Score

The Malnutrition Screening Tool (MST) is a rapid nutrition-risk screen commonly used at hospital admission and in outpatient settings. It is based on recent unintentional weight loss and reduced oral intake/appetite, with higher totals indicating greater malnutrition risk.

Formula: MST total is summed from weighted responses on weight loss and appetite/intake items (0-5).

MST total score

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How It Works

Score Unintentional Weight Loss

Ask whether the patient has lost weight recently without trying. Responses are weighted: no loss = 0; unsure = 2; yes, 1–5 kg = 1; 6–10 kg = 2; 11–15 kg = 3; >15 kg = 4. This single question captures the strongest nutritional-risk signal.

Score Reduced Appetite or Oral Intake

Ask whether the patient has been eating poorly due to reduced appetite. If yes = 1; if no = 0. This item captures anorexia, nausea, or eating difficulty that may not yet produce measurable weight loss.

Sum and Interpret

Add both component scores for a total of 0–5. A total of 0–1 indicates not at risk; 2 or more indicates at-risk status and should trigger dietitian referral or formal nutrition assessment per institutional protocol.

Who Uses the MST Score

Hospital Admission Screening

Inpatient nurses and admitting teams

MST is fast enough to complete in under one minute during routine admission triage, making it ideal for identifying malnutrition risk before formal assessment.

Oncology Nutrition Monitoring

Oncology nurses and cancer dietitians

Validated in cancer populations where treatment-related anorexia and unintentional weight loss are prevalent; MST helps flag patients needing dietitian input during chemotherapy.

Outpatient Geriatric Assessment

Geriatricians and primary care physicians

MST's brevity suits busy outpatient geriatric clinics where rapid functional and nutritional screening must be accomplished within short appointment windows.

Allied Health Triage

Dietitians and nutrition support teams

Positive MST screens prioritize patients for comprehensive nutrition assessment, allowing dietitians to allocate caseload based on risk level.

Pre-operative Nutrition Risk

Surgical teams and anesthesiologists

Identifying malnutrition risk pre-operatively allows time for nutritional optimization to reduce post-operative complications including delayed wound healing and infection.

Serial Monitoring Over Admission

Ward nursing and clinical nutrition teams

Repeat MST assessments during prolonged inpatient stays track changing nutritional risk, especially in patients with fluctuating oral intake or ongoing disease stress.

Pro Tips

Two Questions, Under One Minute

MST requires only two weighted questions and can be administered verbally during standard nursing tasks. Train all admitting staff to complete it routinely without relying on a separate dietetic referral step.

Use Weight History, Not BMI

MST does not rely on BMI, which is often unavailable at admission. Weight-loss history is a more sensitive early signal because BMI can remain 'normal' even with significant depletion.

Document the Reason for Reduced Intake

When appetite is reduced, note the cause (nausea, pain, depression, dysphagia). This context makes the subsequent dietitian assessment more efficient and targeted.

Score 2 = Action, Not Just Documentation

A score of 2 or more should trigger a defined institutional response—dietitian referral or nutrition care plan—not merely a flag in the chart. Build the response pathway before deploying the screen.

Combine With Clinical Observation

MST is a screen, not a diagnosis. Supplement with visible muscle wasting, skin integrity observations, and relevant labs (albumin, prealbumin) to triangulate nutrition status.

Account for Fluid Status

Fluid retention can mask weight loss. In patients with known oedema or ascites, adjust clinical interpretation; a patient may have lost lean mass despite stable or rising weight.

Oncology-Specific Sensitivity

In cancer populations, MST's sensitivity exceeds 93%. Do not skip screening simply because patients appear well-nourished — treatment-related anorexia can precede visible wasting.

Pair With Intervention Protocols

MST works best embedded in a system: positive screen → dietitian assessment → nutrition care plan within 24–48 hours. The screen itself produces no benefit without a linked response.

Common Questions About Your Results

Evidence-Based Methodology

MST is validated across inpatient and ambulatory populations as a practical malnutrition-risk screen.

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

Higher MST totals indicate greater malnutrition-risk signal and need for nutrition-focused follow-up.

When to Use This Tool

Use for rapid first-line nutrition screening in adults, especially during admission or routine risk checks.

Limitations

MST is a screening instrument and does not replace detailed dietetic assessment.

For related assessments, see MUST Score, NRS-2002 and MNA-SF.

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.

Sources

Changelog

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

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