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Printed on 7/20/2026
For informational purposes only. This is not medical advice.
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).
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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.
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.
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.
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 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.
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.
Dietitians and nutrition support teams
Positive MST screens prioritize patients for comprehensive nutrition assessment, allowing dietitians to allocate caseload based on risk level.
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.
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.
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.
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.
When appetite is reduced, note the cause (nausea, pain, depression, dysphagia). This context makes the subsequent dietitian assessment more efficient and targeted.
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.
MST is a screen, not a diagnosis. Supplement with visible muscle wasting, skin integrity observations, and relevant labs (albumin, prealbumin) to triangulate nutrition 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.
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.
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.
MST is validated across inpatient and ambulatory populations as a practical malnutrition-risk screen.
Higher MST totals indicate greater malnutrition-risk signal and need for nutrition-focused follow-up.
Use for rapid first-line nutrition screening in adults, especially during admission or routine risk checks.
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.
April 21, 2026 · trust-baseline
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Screen adults for malnutrition risk using BMI, unplanned weight loss, and acute disease effect with the MUST score.
OpenGeriatricsA guideline-based hospital nutrition risk score where >=3 suggests need for nutrition support.
OpenGeriatricsScreen malnutrition risk in older adults with the MNA-SF 6-item tool (score 0-14).
OpenGeriatricsA lab-based nutrition screening score (0-12) combining albumin, cholesterol, and lymphocyte components.
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