Sequential Organ Failure Assessment Score
Sequential Organ Failure Assessment
Calculate organ dysfunction severity in ICU patients. SOFA score assesses six organ systems and defines sepsis per the Sepsis-3 criteria.
What is the SOFA Score?
The Sequential Organ Failure Assessment (SOFA) score is the gold-standard tool for quantifying organ dysfunction in critically ill patients. It evaluates six organ systems — respiratory, coagulation, hepatic, cardiovascular, neurological, and renal — each scored 0 to 4, giving a total of 0 to 24. According to the Sepsis-3 consensus definitions (2016), sepsis is defined as a life-threatening organ dysfunction caused by infection, operationally identified by an acute increase in SOFA score of ≥2 points from baseline in a patient with suspected infection. SOFA is also used as a prognostic tool, with higher scores correlating with increased ICU mortality.
When to use it
Use in all ICU patients for daily monitoring of organ dysfunction, prognosis estimation, and to operationalise the Sepsis-3 definition of sepsis in patients with suspected infection.
Scoring Criteria
SOFA Score — Variables & Points
Respiratory: PaO₂/FiO₂ ratio (mmHg)
≥400=0, 300–399=1, 200–299=2, 100–199 with ventilation=3, <100 with ventilation=4
Coagulation: Platelets (×10³/µL)
≥150=0, 100–149=1, 50–99=2, 20–49=3, <20=4
Liver: Bilirubin (µmol/L)
<20=0, 20–32=1, 33–101=2, 102–204=3, >204=4
Cardiovascular: Mean arterial pressure / vasopressors
MAP≥70=0, MAP<70=1, dopamine≤5 or dobutamine=2, dopamine>5 or noradrenaline≤0.1=3, dopamine>15 or noradrenaline>0.1=4
Neurological: Glasgow Coma Scale
GCS 15=0, 13–14=1, 10–12=2, 6–9=3, <6=4
Renal: Creatinine (µmol/L) or urine output
<110=0, 110–170=1, 171–299=2, 300–440 or UO<500ml/d=3, >440 or UO<200ml/d=4
Score Interpretation
Low dysfunction
ICU mortality <10%; monitor closely
Moderate dysfunction
ICU mortality ~15–20%; review organ support
High dysfunction
ICU mortality ~40–50%; optimise organ support
Severe dysfunction
ICU mortality >50–80%; consider goals of care
Guideline Recommendation
Sepsis-3 Consensus (JAMA 2016): Sepsis = suspected infection + acute SOFA increase ≥2 from baseline. Septic shock = sepsis + vasopressors needed to maintain MAP ≥65 mmHg + lactate >2 mmol/L despite adequate fluid resuscitation. SOFA replaces SIRS criteria for sepsis diagnosis.
Clinical Pearls
An acute SOFA increase of ≥2 from baseline defines sepsis per Sepsis-3 — baseline is assumed to be 0 in patients without known prior organ dysfunction.
qSOFA (respiratory rate ≥22, altered mentation, SBP ≤100) is the bedside screening tool; SOFA is the confirmatory diagnostic tool.
Serial SOFA scores are more predictive than a single value — a rising score predicts worse outcomes regardless of absolute level.
The cardiovascular component requires knowledge of exact vasopressor dose; use standardised weight-based dosing when recording.
Limitations
Requires ICU-level data (PaO₂ measurement, vasopressor doses) — not fully applicable to general ward patients.
Baseline SOFA is often assumed to be zero, which may underestimate the change in patients with pre-existing organ disease.
Not designed as a direct treatment decision tool — it quantifies dysfunction, not causality.
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Frequently Asked Questions
What SOFA score defines sepsis?
Per the Sepsis-3 consensus (2016), sepsis is defined as an acute increase in SOFA score of ≥2 points from baseline in a patient with suspected or confirmed infection. The SOFA score operationalises the concept of life-threatening organ dysfunction in this context.
What is the difference between SOFA and qSOFA?
SOFA is the full six-organ scoring system requiring lab values and ICU parameters. qSOFA (quick SOFA) is a rapid bedside screen using three criteria: respiratory rate ≥22/min, altered mentation (GCS <15), and systolic BP ≤100 mmHg. qSOFA identifies patients outside the ICU who may be deteriorating; a positive qSOFA (≥2) warrants full SOFA assessment.
What is a normal SOFA score?
A SOFA score of 0 represents no organ dysfunction across all six systems. Scores of 1–3 per organ system reflect mild impairment. For prognosis in ICU patients, a total score ≥11 is associated with >40% ICU mortality in most published cohorts.