NEWS2 and MEWS Criteria for Early Warning Scoring
NEWS2 (National Early Warning Score 2) – The Current Standard
NEWS2 is the recommended early warning score system endorsed by NICE (2024) and has replaced older scoring systems including MEWS in most UK and international acute care settings. 1
Six Physiological Parameters Scored in NEWS2
Each parameter receives 0-3 points based on deviation from normal ranges: 1
| Parameter | Score 3 | Score 2 | Score 1 | Score 0 | Score 1 | Score 2 | Score 3 |
|---|---|---|---|---|---|---|---|
| Respiratory rate (breaths/min) | ≤8 | 9-11 | - | 12-20 | - | 21-24 | ≥25 |
| SpO₂ Scale 1 (%) | ≤91 | 92-93 | 94-95 | ≥96 | - | - | - |
| SpO₂ Scale 2 (%) | ≤83 | 84-85 | 86-87 | 88-92 | 93-94 | 95-96 | ≥97 |
| Supplemental oxygen | - | On oxygen | - | Room air | - | - | - |
| Systolic BP (mmHg) | ≤90 | 91-100 | 101-110 | 111-219 | - | - | ≥220 |
| Heart rate (beats/min) | ≤40 | - | 41-50 | 51-90 | 91-110 | 111-130 | ≥131 |
| Consciousness | - | - | - | Alert | - | - | CVPU* |
| Temperature (°C) | ≤35.0 | - | 35.1-36.0 | 36.1-38.0 | 38.1-39.0 | ≥39.1 | - |
*CVPU = new Confusion, responds to Voice, responds to Pain, or Unresponsive 1
SpO₂ Scale 2 is used specifically for patients with hypercapnic respiratory failure (target saturations 88-92%). 1
NEWS2 Risk Stratification and Clinical Actions
The aggregate score determines risk level and triggers specific monitoring frequencies and antibiotic timing: 1, 2
| NEWS2 Score | Risk Level | Re-assessment Frequency | Antibiotic Timing | Clinical Response |
|---|---|---|---|---|
| 0 | Very low | Per routine protocol | Within 6 hours | Routine monitoring [1] |
| 1-4 | Low | Every 4-6 hours | Within 6 hours | Continue monitoring [1] |
| 5-6 | Moderate | Every 1 hour | Within 3 hours | Escalate to experienced clinician (FY2+) [1,2] |
| ≥7 | High | Every 30 minutes | Within 1 hour | Immediate senior review, consider ICU [1,2] |
Critical Override Criteria – Immediate High-Risk Management
Escalate to high-risk protocols regardless of total NEWS2 score if ANY of the following are present: 1, 2
- Any single parameter scoring 3 points (e.g., respiratory rate ≤8 or ≥25, SpO₂ ≤91%, systolic BP ≤90 mmHg) 1
- Mottled or ashen skin appearance 1, 2
- Non-blanching petechial or purpuric rash 1, 2
- Cyanosis of skin, lips, or tongue 1, 2
Contextual Interpretation Requirements
Always interpret NEWS2 in the context of: 1, 3
- Baseline physiology and comorbidities (chronic cardiac/respiratory disease, spinal injury) 1, 3
- Clinical trajectory – upgrade risk if deteriorating despite interventions 1
- Lack of response to treatment – consider higher actual risk than score suggests 1
MEWS (Modified Early Warning Score) – Historical Context
MEWS has been largely superseded by NEWS2 in clinical practice and is no longer recommended by current NICE guidelines. The provided evidence does not contain specific MEWS criteria because it has been replaced by the more validated NEWS2 system. 1
Why NEWS2 Replaced MEWS
- NEWS2 provides standardized national risk stratification for sepsis and acute deterioration 1
- NEWS2 has superior evidence base for predicting mortality and ICU admission 1
- NEWS2 includes consciousness assessment (CVPU) and supplemental oxygen requirement, which MEWS lacked 1
- NEWS2 has validated risk thresholds tied to specific clinical actions and antibiotic timing 1, 2
Common Pitfalls and Clinical Caveats
Do not rely solely on aggregate scores – a single parameter scoring 3 points mandates escalation even if total score is low. 1
Do not delay antibiotics beyond the specified timeframes (1 hour for high-risk, 3 hours for moderate-risk) – these are maximum windows, not targets. 2
Do not ignore clinical gestalt – if the patient appears unwell or is deteriorating, escalate regardless of NEWS2 score. 1
Adjust interpretation for chronic conditions – patients with baseline tachycardia, tachypnea, or altered consciousness may have falsely elevated scores. 1, 3
Use SpO₂ Scale 2 for COPD patients with known hypercapnic respiratory failure to avoid penalizing appropriate target saturations. 1