Reference — Emergency Nursing
Sepsis Criteria Reference
Quick reference for sepsis diagnostic criteria — SIRS criteria, qSOFA bedside score, Sepsis-3 organ dysfunction indicators, lactate thresholds, and septic shock definition.
Educational use only. This content is intended for nursing students and exam preparation. Sepsis definitions are based on Sepsis-3 (2016) consensus criteria. Clinical decisions require licensed professional judgment. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Sepsis-3 Definition (2016)
Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection (Singer et al., JAMA 2016).
| Term | Definition |
|---|---|
| Infection | Suspected or confirmed microbial invasion — bacteria, fungi, viruses, or parasites |
| Sepsis | Life-threatening organ dysfunction from dysregulated host response to infection. Clinically: suspected infection + SOFA score increase ≥2 from baseline. |
| Septic shock | Sepsis + vasopressor requirement to maintain MAP ≥65 mmHg + serum lactate >2 mmol/L despite adequate fluid resuscitation. In-hospital mortality >40%. |
| Bacteremia | Bacteria in the bloodstream — does NOT equal sepsis unless organ dysfunction present |
| SIRS (Systemic Inflammatory Response Syndrome) | Nonspecific inflammatory response — can be from infection (sepsis) or non-infectious causes (trauma, burns, pancreatitis). No longer required for sepsis diagnosis in Sepsis-3. |
SIRS Criteria (Historical Reference)
SIRS criteria were used pre-Sepsis-3 (before 2016). While no longer the defining criteria for sepsis, they remain clinically relevant for bedside recognition. SIRS requires ≥2 of 4 criteria:
| Parameter | SIRS Criterion | Clinical Note |
|---|---|---|
| Temperature | >38°C (100.4°F) OR <36°C (96.8°F) | Hypothermia in sepsis = poor prognosis. Do NOT rule out sepsis because patient is afebrile. |
| Heart Rate | >90 beats per minute | Tachycardia compensates for decreased stroke volume and cardiac output |
| Respiratory Rate | >20 breaths per minute OR PaCO₂ <32 mmHg | Hyperventilation compensates for metabolic acidosis from tissue hypoperfusion |
| WBC | >12,000/μL OR <4,000/μL OR >10% bands | Bandemia (>10% bands) = immature neutrophils = bone marrow releasing reserve in acute infection |
SIRS is nonspecific — can be present in pancreatitis, trauma, burns, post-surgery. Presence of SIRS with suspected infection raises concern for sepsis but SIRS alone does not confirm sepsis.
qSOFA Score (Bedside Screening)
The quick SOFA (qSOFA) is a rapid bedside screening tool — no labs required. A score ≥2 predicts poor outcome and should trigger immediate sepsis evaluation and treatment.
| qSOFA Criterion | Threshold | Points | Rationale |
|---|---|---|---|
| Altered mentation | GCS <15 OR new confusion, agitation | 1 | Cerebral hypoperfusion or toxin effect |
| Respiratory rate | ≥22 breaths per minute | 1 | Respiratory compensation for metabolic acidosis |
| Systolic blood pressure | ≤100 mmHg | 1 | Vasodilation and cardiac depression from septic mediators |
qSOFA 0–1
Low risk
Continue monitoring. Reassess if clinical condition changes.
qSOFA 2
High risk — act now
Initiate sepsis workup: blood cultures, lactate, CBC, BMP. Contact provider immediately.
qSOFA 3
Critical — likely septic shock
Immediate provider notification. Sepsis bundle. Consider ICU. Vasopressors likely needed.
Organ Dysfunction Indicators (SOFA Score)
| Organ System | Indicator | Dysfunction Finding |
|---|---|---|
| Respiratory | PaO₂/FiO₂ ratio | <400 = mild; <300 = moderate; <200 with ventilation = severe (ARDS threshold) |
| Coagulation | Platelet count | <150,000/μL = mild; <100,000 = moderate; <50,000 = severe |
| Liver | Bilirubin | >1.2 mg/dL = mild dysfunction; >12 mg/dL = severe |
| Cardiovascular | MAP and vasopressor requirement | MAP <70 mmHg OR vasopressor requirement (dopamine, norepinephrine, epinephrine, vasopressin) |
| Central Nervous System | Glasgow Coma Scale | GCS <15 = mild; GCS <13 = moderate; GCS <10 = severe |
| Renal | Creatinine or urine output | Creatinine >1.2 mg/dL = mild; UO <0.5 mL/kg/hr for ≥6 hrs = moderate; creatinine >5.0 or UO <0.3 mL/kg/hr = severe |
SOFA score ≥2 from baseline = organ dysfunction consistent with sepsis. Each point of SOFA increase is associated with approximately 10% increase in hospital mortality.
Lactate — Clinical Interpretation
| Lactate Level | Clinical Significance | Action |
|---|---|---|
| <2 mmol/L | Normal — adequate tissue perfusion | Continue monitoring; lower clinical concern if clinically stable |
| 2–4 mmol/L | Elevated — tissue hypoperfusion; sepsis with organ dysfunction | Initiate sepsis protocol, fluid resuscitation, reassess in 2 hours post-resuscitation |
| >4 mmol/L | Severely elevated — septic shock criterion (regardless of BP) | Highest urgency — vasopressors, ICU admission, immediate source control, broad-spectrum antibiotics |
| Lactate clearance | Reduction ≥10–20% after 2 hours of resuscitation = adequate response | Failure to clear lactate = inadequate resuscitation or ongoing source — escalate care |
Septic Shock Criteria
Septic Shock (Sepsis-3) — ALL criteria must be present:
In-hospital mortality for septic shock: >40%. Early recognition and bundle adherence (within 1–3 hours) significantly reduces mortality.
Related Resources
Standards & sources
Fact-checked Jun 20, 2026This page is written to align with Emergency Nurses Association (ENA) · AHA ACLS / PALS Guidelines · Advanced Trauma Life Support (ATLS). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →