Clinical Decision-Making
qSOFA Score and Sepsis-3: Complete Clinical Guide
qSOFA (altered mentation, RR ≥22, SBP ≤100) was introduced with Sepsis-3 as a bedside prompt to identify patients with suspected infection at risk of poor outcomes outside the ICU. Score ≥2 predicts 3–14× higher mortality across risk strata. qSOFA is NOT a sepsis diagnostic criterion — it's a prompt to investigate further. SOFA ≥2 in a patient with suspected infection defines sepsis.
TL;DR: qSOFA (altered mentation, RR ≥22, SBP ≤100) was introduced with Sepsis-3 as a bedside prompt to identify patients with suspected infection at risk of poor outcomes outside the ICU. Score ≥2 predicts 3–14× higher mortality. qSOFA is NOT a sepsis diagnostic criterion — it's a prompt to investigate further. SOFA ≥2 in a patient with suspected infection defines sepsis. SIRS is no longer part of the Sepsis-3 framework.
The Sepsis-3 Revolution
Sepsis-1 and Sepsis-2 defined sepsis as infection + two or more SIRS criteria. But SIRS is neither specific nor prognostically meaningful. In 2016, Sepsis-3 redefined sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection.
qSOFA Score
| Criterion | Definition | Points |
|---|---|---|
| Altered mentation | GCS <15 | 1 |
| Respiratory rate | ≥22/min | 1 |
| Systolic BP | ≤100 mmHg | 1 |
Score ≥2 = elevated risk for poor outcome → evaluate for organ dysfunction (SOFA).
SOFA Score in Sepsis Diagnosis
SOFA quantifies organ dysfunction across six systems. Acute increase of ≥2 points from baseline + suspected infection = sepsis.
Septic Shock Definition
Septic shock = sepsis + vasopressor requirement to maintain MAP ≥65 + lactate >2 mmol/L despite adequate resuscitation. Hospital mortality ~40–50%.
qSOFA vs SIRS vs SOFA
| Feature | SIRS | qSOFA | SOFA |
|---|---|---|---|
| Variables | 4 | 3 | 24 |
| Labs needed | WBC | None | Extensive |
| Sensitivity | ~75% | ~60% | ~87% |
| Specificity for mortality | ~27% | ~73–97% | Moderate |
| AUROC mortality (non-ICU) | ~0.76 | ~0.81 | ~0.79 |
| Guideline status | Deprecated | Bedside prompt | Defines sepsis |
Evidence and Guidelines
Seymour CW et al. (2016) validated Sepsis-3 criteria in over 1.3 million encounters. qSOFA had AUROC 0.81 for non-ICU mortality (p<0.001 vs SIRS 0.76). JAMA. 2016;315(8):762–774. PMID: 26903335.
Serafim R et al. (2018) meta-analysis: SIRS more sensitive for sepsis diagnosis; qSOFA better for predicting mortality. Chest. 2018;153(3):646–655. PMID: 29289687.
References
- Seymour CW et al. JAMA. 2016;315(8):762–774. PMID: 26903335.
- Serafim R et al. Chest. 2018;153(3):646–655. PMID: 29289687.
- Giamarellos-Bourboulis EJ et al. Clin Microbiol Infect. 2017;23(2):104–109. PMID: 27856268.
- Evans L et al. Crit Care Med. 2021;49(11):e1063–e1143. PMID: 34605781.
Related calculators
- SOFA Score Calculator - Critical Care