Critical Care
SOFA Score
Sequential organ failure assessment.
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Background
The Sequential Organ Failure Assessment (SOFA) score quantifies the degree of dysfunction across six organ systems in critically ill patients: respiration, coagulation, liver, cardiovascular, central nervous system and renal. Each system is scored from 0 (normal) to 4 (most abnormal), giving a total from 0 to 24. It was developed to describe and track organ dysfunction over time rather than to predict outcome in any single patient. Within the Sepsis-3 definition, an acute rise in SOFA is central to identifying sepsis in patients with suspected infection.
Interpreting the result
A higher total reflects more severe multi-organ dysfunction and correlates with greater mortality. Broadly, lower totals (around 0–6) indicate less organ dysfunction, intermediate totals (around 7–9) moderate dysfunction, and totals of 10 or more substantial organ failure with high associated mortality. Crucially, the trend matters as much as the absolute value: a rise of 2 or more points in a patient with suspected infection is consistent with sepsis under the Sepsis-3 definition.
Advice
Bilirubin and creatinine in mg/dL. An acute rise in SOFA of ≥2 points in suspected infection is consistent with sepsis (Sepsis-3).
Worked example
A ventilated patient with PaO₂/FiO₂ < 200 on support (3), platelets of 90 ×10³/µL (2), bilirubin 3 mg/dL (2), MAP < 70 (1), GCS 13 (1) and creatinine 2.5 mg/dL (2) scores 3 + 2 + 2 + 1 + 1 + 2 = 11. This indicates significant multi-organ dysfunction.
Pearls / pitfalls
- Note the units — bilirubin and creatinine are scored in mg/dL in the original SOFA, so convert if your laboratory reports µmol/L.
- The cardiovascular criterion depends on vasoactive support; document the agent and infusion category used when scoring.
- A single SOFA value describes severity at one moment — serial scores are more informative for tracking the course of illness.
- SOFA is a descriptive and risk-stratification tool, not a bedside diagnostic test for sepsis on its own; it complements clinical assessment.
Evidence & validation
Developed by Vincent and colleagues for the European Society of Intensive Care Medicine and validated in numerous critical-care cohorts. It is embedded in the Sepsis-3 consensus definitions, where an acute change in SOFA of 2 or more points operationalises organ dysfunction due to infection.
Frequently asked questions
How does SOFA relate to sepsis (Sepsis-3)?
Under the Sepsis-3 definition, sepsis is suspected or proven infection together with an acute increase in the SOFA score of 2 or more points, reflecting organ dysfunction. The change in score, rather than a single value, is what matters for this definition.
What is the difference between SOFA and qSOFA?
qSOFA is a rapid bedside screen using respiratory rate, altered mentation and low systolic blood pressure, with no laboratory tests. The full SOFA score uses six organ systems and laboratory data and quantifies the actual degree of organ dysfunction.
Do I assume a SOFA of 0 at baseline?
In patients without known pre-existing organ dysfunction, a baseline SOFA of 0 is generally assumed, so the presenting score also represents the acute change. In those with chronic organ dysfunction, the rise from baseline should be considered.
Why are bilirubin and creatinine in mg/dL?
The original SOFA score was defined using mg/dL thresholds. If your laboratory reports these in µmol/L you must convert the values before applying the cut-offs, or use a calculator that accepts SI units.
References
- Vincent JL, Moreno R, Takala J, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. Intensive Care Med. 1996;22(7):707–710.
- Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801–810.
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