Why a new Sequential Organ Failure Assessment score: rationale and development of Sequential Organ Failure Assessment-2.

PURPOSE OF REVIEW: For three decades, the Sequential Organ Failure Assessment (SOFA) score has been central to critical care, offering a simple, reproducible measure of organ dysfunction. Since the original score [Sequential Organ Failure Assessment-1 (SOFA-1)] [1], advances in organ support, drugs, and monitoring, and an ageing, comorbid population have reshaped practice and rendered several tools outdated. This prompted an international initiative to modernize SOFA while preserving its core strengths: simplicity, reproducibility, feasibility across diverse settings, and longitudinal assessment of organ dysfunction.

RECENT FINDINGS: SOFA-2 was developed through a modified Delphi process with 60 international experts and dedicated methodology and validation committees. Expert consensus, systematic reviews, and analyses of multinational databases (high-income, middle-income, and lower-middle-income systems) established its face, content, and predictive validity. The six original organ systems were retained; the gastrointestinal and immune domains were examined but not included because current datasets did not support them. SOFA-2 keeps the architecture of SOFA-1 while updating definitions, reflecting contemporary therapies, and standardizing missing-data handling and the scoring of acute-on-chronic dysfunction.

SUMMARY: SOFA-2 is an evolution rather than a reinvention. It must now be tested in the real-world - within definitions such as Sepsis-3, across its derived variables (admission, maximum, delta, discharge), and in varied settings, including low-income and middle-income countries.