Grading organ failure
The Sequential Organ Failure Assessment (SOFA) score was created in 1994 by a European working group led by Jean-Louis Vincent to describe, day by day, how well the organs of critically ill patients are working. It has since become the backbone of the international definition of sepsis.
The six organ systems
Each system scores from 0 (normal) to 4 (most severe):
| System | Measure | 0 | 4 |
|---|---|---|---|
| Respiration | PaO₂/FiO₂ (mmHg) | 400 or more | below 100 with respiratory support |
| Coagulation | Platelets (×10³/µL) | 150 or more | below 20 |
| Liver | Bilirubin (mg/dL) | below 1.2 | 12 or more |
| Cardiovascular | Mean pressure and vasopressors | MAP 70 or more | high-dose norepinephrine, epinephrine or dopamine |
| Nervous system | Glasgow coma scale | 15 | below 6 |
| Kidneys | Creatinine (mg/dL) or urine output | below 1.2 | 5.0 or more, or below 200 mL/day |
The total ranges from 0 to 24. Use the worst value of each measure over the past 24 hours.
Worked example
A patient has a PaO₂/FiO₂ ratio of 320 (1 point), a mean arterial pressure of 65 mmHg without vasopressors (1 point) and a creatinine of 1.5 mg/dL (1 point). Everything else is normal. The SOFA score is 3. In the 2001 Ferreira study, patients admitted with an initial score of 2 or 3 had an ICU mortality of about 6.4%.
Sepsis-3
The 2016 Sepsis-3 consensus defined sepsis as life-threatening organ dysfunction caused by a dysregulated response to infection. In practice, it is identified by an acute rise of 2 points or more in the SOFA score in a patient with a suspected infection. If the baseline is unknown, it is assumed to be zero. Septic shock adds the need for vasopressors to keep the mean arterial pressure at 65 mmHg or above, with a lactate above 2 mmol/L despite fluids.
Mortality and trend
In Ferreira’s 2001 study of ICU patients, mortality rose with the initial score: about 6% for 2 or 3 points, 20% for 4 to 7, 33% for 8 or 9, 50% for 10 or 11 and over 95% above 11. A score that rises during the first 48 hours is associated with higher mortality than one that falls, whatever the starting value.
Limits
SOFA needs blood tests, including an arterial blood gas, so it is mainly used in hospital and intensive care. Sedation makes the Glasgow component hard to assess; the usual practice is to score the presumed value without sedation. The score was designed to describe organ dysfunction, not to make treatment decisions for an individual patient.
This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.