SOFA Score: Clinical Significance and Management
What is the SOFA Score?
The Sequential Organ Failure Assessment (SOFA) score is a validated tool that evaluates dysfunction across six organ systems (respiratory, cardiovascular, brain, liver, kidney, and hemostasis), with each system scored 0-4 points for a total possible score of 0-24, where higher scores indicate worse organ dysfunction and increased mortality risk. 1, 2
The SOFA-2 score, updated in 2025, reflects contemporary critical care practice with revised thresholds and organ support variables, maintaining an AUROC of 0.79 for predicting ICU mortality. 3
Core Components of SOFA-2
Respiratory system: Assessed via PaO2/FiO2 ratio, ranging from 0 (≥400 mmHg) to 4 (<100 mmHg with mechanical ventilation). 1, 4
Cardiovascular system: Evaluated through mean arterial pressure and vasopressor requirements, from 0 (MAP ≥70 mmHg) to 4 (high-dose norepinephrine or epinephrine). 1
Brain (neurological): Measured using Glasgow Coma Scale, with score of 4 indicating GCS <6. 1
Liver (hepatic): Assessed via bilirubin levels, from 0 (<20 μmol/L or <1.2 mg/dL) to 4 (>204 μmol/L or >12.0 mg/dL). 1
Kidney (renal): Evaluated through creatinine levels and urine output, from 0 (<110 μmol/L) to 4 (>440 μmol/L or >5.0 mg/dL, or <200 mL/day urine output). 1
Hemostasis (coagulation): Measured by platelet count, from 0 (≥150 × 10³/μL) to 4 (<20 × 10³/μL). 1
Clinical Significance by Score Range
Low Scores (SOFA 0-6)
A SOFA score of 2 indicates mild single-organ dysfunction and carries relatively low mortality risk in general ICU populations. 1
In the presence of documented or suspected infection, a SOFA score increase of ≥2 points from baseline defines sepsis according to Sepsis-3 criteria, triggering immediate broad-spectrum antibiotics within 1 hour, fluid resuscitation, and source control. 1, 2
Do not assume sepsis based solely on SOFA ≥2 without documented infection—clinical context is essential. 1
Moderate Scores (SOFA 7-10)
Scores in this range indicate significant multi-organ dysfunction with substantially increased mortality risk. 1
Mortality risk increases substantially when scores exceed 7-8 points. 1
These patients require intensive monitoring with SOFA reassessment every 48-72 hours to track disease trajectory. 1, 5
High Scores (SOFA >10)
A SOFA score >10 predicts mortality exceeding 80-90%, with scores >11 associated with >90% mortality. 1, 2
At this threshold, discuss goals of care and appropriateness of invasive interventions versus palliative measures, as mortality exceeds 90%. 1
Very high total scores are worrisome and generally indicate poor prognosis, particularly when scores increase across multiple organ systems. 6
Management Algorithm Based on SOFA Score
Initial Assessment and Scoring
Calculate SOFA score on ICU admission using the most abnormal values from the first 24 hours. 1, 2
Document baseline SOFA score to enable calculation of delta-SOFA (Δ-SOFA), which provides valuable prognostic information about disease progression. 1, 5
Serial Monitoring Protocol
Reassess SOFA scores every 48-72 hours throughout the ICU stay to track disease progression and treatment response. 1, 7
Delta-SOFA (change from baseline) is more powerful than static scores in predicting hospital mortality (AUROC 0.81 vs 0.75). 5
An increase of ≥2 SOFA points signals treatment failure requiring escalation of care. 1, 5
Decreasing SOFA scores indicate treatment response—33% of survivors show decreasing scores compared to only 21% of non-survivors. 7
Organ-Specific Interventions
Implement targeted supportive care for each dysfunctional organ system while treating the underlying etiology. 1
For cardiovascular dysfunction: Ensure adequate perfusion, initiate vasopressors if MAP <65 mmHg despite fluids. 1
For respiratory dysfunction: Optimize oxygenation and ventilation strategies based on PaO2/FiO2 ratio. 1
For sepsis with SOFA ≥2: Initiate early broad-spectrum antibiotics within 1 hour, implement fluid resuscitation, and consider hydrocortisone if septic shock develops (though benefits are modest). 1
Coagulopathy Screening
Screen all septic patients for coagulopathy using the Sepsis-Induced Coagulopathy (SIC) scoring system, which incorporates SOFA score ≥2 as one component. 1
SIC score ≥4 indicates early coagulopathy requiring closer monitoring. 1
Critical Limitations and Pitfalls
Do not use SOFA alone for triage decisions in non-pandemic settings, as it lacks validation for resource allocation at low scores. 1
SOFA does not consider patient age or comorbidities, unlike APACHE II scoring systems. 1, 2, 4
SOFA is not suitable for categorizing patients with low-moderate severity without sepsis or organ failure in the first 24 hours of hospital admission. 2
The score has lower predictive value than APACHE II for mortality in certain conditions like complicated intra-abdominal infections (AUROC 0.75 vs 0.81). 2
SOFA scores have not been validated as predictors of mortality in infants and children. 6
Gastrointestinal and immune dysfunction could not be incorporated into SOFA-2 due to insufficient data and lack of content validity. 1, 8, 3
Special Considerations for Mass Casualty Events
In anthrax or other mass-casualty incidents, mechanisms should capture SOFA scores and other objective scoring systems for septic patients. 6
Monitoring organ dysfunction over time is most useful; failure of clinical improvement or increasing scores across multiple organ systems indicates poor prognosis. 6
In resource-limited scenarios, patients requiring maximum ventilator settings or with vasopressor-resistant shock are generally lower priority for limited resources like antitoxin or ICU beds. 6
Consider basic clinical discriminators (need for mechanical ventilation, hemodynamic instability requiring vasopressors) alongside SOFA for resource prioritization. 6
Near real-time data collection and analysis during mass-casualty events helps develop decision tools for scarce resource allocation. 6
Prognostic Utility in Research
SOFA is valuable for research purposes, audit, and comparing outcomes across different ICU populations. 1, 4
When using SOFA as a research endpoint, clearly define primary outcomes (mortality, organ dysfunction, length of stay) and establish standardized protocols for collecting physiological parameters. 4
Document timing of measurements relative to admission and include relevant demographic and clinical variables that may influence scores. 4