Acute Medicine
MEWS (Modified Early Warning Score)
Older early-warning score (NEWS2 now preferred in the UK).
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
The Modified Early Warning Score (MEWS) is an aggregate physiological score designed to flag clinical deterioration in hospitalised adults. It assigns points to derangements in systolic blood pressure, heart rate, respiratory rate, temperature and conscious level (assessed by the AVPU scale). The points are summed, with higher totals indicating greater physiological disturbance and a higher risk of deterioration. In the UK, the National Early Warning Score 2 (NEWS2) has largely superseded MEWS as the recommended national standard.
Interpreting the result
A higher total indicates greater physiological derangement. Broadly, a score of 0–2 is low risk, 3–4 warrants increased monitoring and a score of 5 or more (or 3 in any single parameter) should trigger urgent clinical review and escalation. The single-parameter trigger is important, as a severe abnormality in one vital sign can be dangerous even when the total is modest. MEWS supports, but does not replace, clinical concern and local escalation policy.
Advice
A total ≥5 (or 3 in any single parameter) warrants urgent review. Prefer NEWS2 in UK hospital settings.
Worked example
A patient with a systolic BP of 95 mmHg (1), heart rate 115/min (2), respiratory rate 22/min (2), temperature 37.5°C (0) and responsive only to voice (1) scores 1 + 2 + 2 + 0 + 1 = 6. This exceeds the threshold of 5 and should prompt urgent review.
Pearls / pitfalls
- A single parameter scoring 3 should trigger review even if the total score is low.
- In UK health service settings, NEWS2 is the preferred and recommended standard; use MEWS only where it remains in local use.
- It is a screen for deterioration, not a diagnosis — a high score should prompt assessment for the underlying cause.
- Scores can be confounded by chronic abnormalities (e.g. chronic hypertension or established hypoxia), so interpret in context.
Evidence & validation
Validated by Subbe and colleagues in acute medical admissions as a predictor of deterioration and adverse outcomes. In UK practice it has been superseded by NEWS2, which the Royal College of Physicians recommends as the standard track-and-trigger system for acutely ill adults.
Frequently asked questions
Should I use MEWS or NEWS2?
In the UK, NEWS2 is the recommended national standard for detecting deterioration in acutely ill adults and is preferred over MEWS. MEWS should only be used where it remains embedded in local systems.
What score triggers urgent review?
A total score of 5 or more generally warrants urgent review. In addition, a score of 3 in any single parameter should trigger escalation even if the overall total is low.
Does a normal score mean the patient is safe?
No. A low score is reassuring but does not exclude serious illness. Clinical concern should always override a reassuring score, and the patient should be reassessed if their condition changes.
Why does conscious level use AVPU?
MEWS uses the simple AVPU scale (Alert, responds to Voice, responds to Pain, Unresponsive) as a quick bedside assessment of consciousness. NEWS2 uses a similar approach but adds new confusion to the assessment.
References
- Subbe CP, Kruger M, Rutherford P, Gemmel L. Validation of a modified Early Warning Score in medical admissions. QJM. 2001;94(10):521–526.
- Royal College of Physicians. National Early Warning Score (NEWS) 2: standardising the assessment of acute illness severity in UK practice. 2017.
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