SOFA Score Calculator – Organ Failure Assessment

The Sequential Organ Failure Assessment (SOFA) score is one of the most widely used tools in intensive care medicine. Developed in 1996 by a working group of the European Society of Intensive Care Medicine, it was originally called the Sepsis-related Organ Failure Assessment before being renamed to reflect its broader applicability in any critically ill patient, not just those with suspected infection. The score evaluates six organ systems — respiratory, coagulation, hepatic, cardiovascular, renal, and neurological — each rated from 0 (normal function) to 4 (severe dysfunction), yielding a maximum total of 24 points. Each organ system uses a specific, validated parameter. Respiratory function is measured by the PaO2/FiO2 ratio, which compares the arterial oxygen partial pressure with the fraction of inspired oxygen. Normal values exceed 400 mmHg; ratios below 100 indicate severe oxygenation failure, often requiring mechanical ventilation. Coagulation is assessed via platelet count: a normal value is above 150 ×10³/μL, and counts below 20 signal critical thrombocytopenia. Hepatic function uses total bilirubin, with values above 12 mg/dL marking severe dysfunction. Cardiovascular assessment combines mean arterial pressure with vasopressor requirements, reflecting both hemodynamic status and the intensity of pharmacological support needed. Renal function incorporates serum creatinine and 24-hour urine output, capturing both glomerular filtration and tubular function. Finally, the Glasgow Coma Scale quantifies neurological status on a standardized scale from 3 (unresponsive) to 15 (fully conscious). The SOFA score has become central to the Sepsis-3 definition, where an acute increase of 2 or more SOFA points in a patient with a suspected infection is used to define sepsis. This redefinition, published in JAMA in 2016, replaced older criteria based on the systemic inflammatory response syndrome (SIRS) and has been adopted worldwide. A variant, the quick SOFA (qSOFA), uses just three bedside criteria — altered mentation, respiratory rate above 22, and systolic blood pressure below 100 — as a rapid screening tool before full SOFA scoring. Predictive accuracy of the SOFA score has been confirmed in numerous validation studies. A baseline SOFA score above 9 is associated with ICU mortality rates of 40–50%, while scores of 12 or above carry mortality risks exceeding 80%. Importantly, the change in SOFA score over the first 48 hours of ICU admission is at least as important as the initial value: patients whose scores improve tend to do better than their admission score alone would suggest, while deteriorating scores are a powerful indicator of poor prognosis. Beyond prognosis, SOFA scores guide clinical decision-making around ICU triage, organ support escalation, and resource allocation. During pandemics or mass-casualty events, SOFA scores have been proposed as part of crisis standards of care frameworks for ventilator allocation. Regular serial assessments — typically every 24 to 48 hours — allow clinicians to track trajectory and adjust treatment. This calculator is intended for educational purposes and clinical decision support, and should always be interpreted in the context of the full clinical picture and the expertise of the treating team.