Best Sepsis Early Warning System
The National Early Warning Score 2 (NEWS2) is the best sepsis early warning system for adults in acute hospital settings, demonstrating superior diagnostic accuracy compared to other screening tools including qSOFA. 1, 2
Why NEWS2 is Superior
NEWS2 consistently outperforms other sepsis screening tools in detecting patients at risk of severe illness or death from sepsis. Multiple studies demonstrate NEWS2's superiority:
- NEWS2 achieved an AUC of 0.80-0.82 for detecting sepsis with organ dysfunction, significantly higher than qSOFA's AUC of 0.62-0.70 3, 4
- In immunocompromised patients, NEWS2 maintains high prognostic accuracy while qSOFA underestimates risk, particularly in patients on high-dose glucocorticoids 5
- NICE guidelines (2024) specifically recommend NEWS2 as the standard tool for risk stratification in acute hospital, mental health, and ambulance settings 1
How to Use NEWS2
Calculate the Score
NEWS2 uses six physiological parameters 1:
- Respiration rate
- Oxygen saturation (with adjustment for hypercapnic respiratory failure)
- Supplemental oxygen requirement
- Systolic blood pressure
- Pulse rate
- Level of consciousness (Alert vs CVPU)
- Temperature
Risk Stratification
Interpret NEWS2 scores as follows 1, 2:
- High risk (≥7): Severe illness or death from sepsis likely
- Moderate risk (5-6): Moderate risk of severe illness or death
- Low risk (1-4): Low risk of severe illness or death
- Very low risk (0): Very low risk
Critical Single Parameters
A score of 3 in any single parameter indicates increased sepsis risk regardless of total score 1. This distinction is crucial for catching early deterioration.
Override Criteria
Evaluate risk as higher than NEWS2 suggests if any of these clinical signs are present 1, 2:
- Mottled or ashen appearance
- Non-blanching petechial or purpuric rash
- Cyanosis of skin, lips, or tongue
Monitoring Frequency Based on Risk
Re-calculate NEWS2 at specific intervals 1:
- High risk: Every 30 minutes
- Moderate risk: Every hour
- Low risk: Every 4-6 hours
- Very low risk: Per standard protocol
Alternative Tools and Their Limitations
qSOFA Performance
While qSOFA demonstrates high specificity (AUC >0.8), its sensitivity is inadequate for early sepsis detection 6, 7. The 2021 Surviving Sepsis Campaign Guidelines specifically discourage relying solely on qSOFA 6.
Enhancing qSOFA
If qSOFA must be used, combining it with quantitative capillary refill time (Q-CRT) or lactate levels improves performance 6:
- qSOFA + Q-CRT: AUC 0.821, sensitivity 83.3%, specificity 81.4%
- qSOFA + lactate: AUC 0.844, sensitivity 87.5%, specificity 81.4%
However, this still does not match NEWS2's standalone performance 3.
SOFA Score
SOFA score is designed for ICU patients to assess organ dysfunction severity, not for early warning 1. It requires laboratory values and is too complex for rapid bedside screening 1.
SIRS Criteria
SIRS has the lowest predictive ability (AUC ~0.6) and has been de-emphasized in modern sepsis definitions 6, 7. The Sepsis-3 guidelines moved away from SIRS due to its non-specificity 7.
Implementation Strategy
Routine screening using NEWS2 is recommended for all potentially infected seriously ill patients 1. The Surviving Sepsis Campaign emphasizes that sepsis screening tools implementation has been associated with decreased sepsis-related mortality 1.
Resource-Limited Settings
In low-resource settings where laboratory tests are limited, early warning scores using simple physiological parameters become even more critical 1. NEWS2's reliance on easily measurable bedside parameters makes it ideal for these environments 1.
Common Pitfalls to Avoid
- Do not ignore a single parameter score of 3 even if total NEWS2 is low 1
- Always interpret NEWS2 in context of underlying physiology and comorbidities 1
- Do not delay reassessment if condition deteriorates despite initial low score 1
- In immunocompromised patients, be especially vigilant as qSOFA may underestimate risk while NEWS2 maintains accuracy 5
- Do not use qSOFA alone for sepsis screening in emergency departments 6, 3
Integration with Treatment Protocols
NEWS2 risk level should guide antibiotic timing 2:
- High-risk patients require antimicrobial therapy within 1 hour
- Risk stratification helps prioritize interventions and resource allocation
Performance improvement efforts using NEWS2-based protocols have been associated with improved patient outcomes and decreased mortality 1.