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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.
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.
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.
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
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
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.
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.
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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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.
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.
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.