SOFA Score Calculator

How to Use This Calculator

1. Enter P/F ratio, platelets, bilirubin, vasopressor status, GCS, and creatinine.
2. SOFA score (0–24), component breakdown, and mortality estimate display instantly.
3. Delta SOFA tab: enter baseline and current SOFA to assess organ dysfunction trajectory.
4. Professional tier adds baseline SOFA input and Sepsis-3 ΔSOFA ≥2 assessment.

Formula

Example

Frequently Asked Questions

• What is the SOFA score? ▼
  The Sequential (Sepsis-related) Organ Failure Assessment (SOFA) score was originally developed by Vincent and colleagues and published in Intensive Care Medicine in 1996 as the Sepsis-related Organ Failure Assessment score, later renamed Sequential to reflect its utility in serial tracking. It quantifies the degree of organ dysfunction across six physiological systems, each scored 0–4 based on the degree of derangement, for a total possible score of 0–24. The six components are: (1) Respiratory — scored by PaO2/FiO2 ratio (P/F ratio): ≥400 = 0; 300–399 = 1; 200–299 = 2; 100–199 = 3; <100 = 4. (2) Coagulation — platelet count (×10³/µL): ≥150 = 0; 100–149 = 1; 50–99 = 2; 20–49 = 3; <20 = 4. (3) Liver — bilirubin (mg/dL): <1.2 = 0; 1.2–1.9 = 1; 2.0–5.9 = 2; 6.0–11.9 = 3; ≥12 = 4. (4) Cardiovascular — MAP and vasopressor use: MAP ≥70 = 0; MAP <70 = 1; dopamine ≤5 mcg/kg/min or dobutamine = 2; dopamine >5 or norepinephrine/epinephrine ≤0.1 = 3; dopamine >15 or norepinephrine/epinephrine >0.1 = 4. (5) Central nervous system — GCS score: 15 = 0; 13–14 = 1; 10–12 = 2; 6–9 = 3; <6 = 4. (6) Renal — creatinine (mg/dL): <1.2 = 0; 1.2–1.9 = 1; 2.0–3.4 = 2; 3.5–4.9 = 3; ≥5 = 4.
• How is SOFA used in sepsis diagnosis? ▼
  In the Sepsis-3 consensus framework (Singer et al. JAMA 2016), sepsis is formally defined as "life-threatening organ dysfunction caused by a dysregulated host response to infection," operationally defined as a suspected or confirmed infection plus an acute increase in SOFA score of 2 or more points above the patient's baseline. The baseline SOFA is assumed to be zero for patients without pre-existing organ dysfunction; for patients with known chronic organ disease (chronic kidney disease, cirrhosis, heart failure), the baseline should be estimated from recent outpatient laboratory values. A ΔSOFA ≥2 indicates acute organ dysfunction and confers an approximate in-hospital mortality of 10% or more, making it clinically significant. Septic shock is further defined within Sepsis-3 as sepsis with circulatory and cellular/metabolic dysfunction manifest as both persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND serum lactate >2 mmol/L despite adequate volume resuscitation — hospital mortality associated with septic shock exceeds 40%. The SOFA score was chosen over SIRS criteria for the Sepsis-3 definition because SIRS reflects inflammation (not necessarily pathological), while SOFA reflects organ dysfunction, which is the physiologically relevant and prognostically important consequence of sepsis. SOFA ≥2 identifies patients with risk of mortality that warrants ICU-level care.
• What is a Delta SOFA and why does it matter? ▼
  Delta SOFA (ΔSOFA) refers to the change in SOFA score between two time points — most commonly between the baseline (pre-admission or admission value) and the current measurement. It is the central metric in the Sepsis-3 definition, where ΔSOFA ≥2 from baseline identifies acute organ dysfunction attributable to sepsis. ΔSOFA matters for several reasons. First, diagnosis: a single high SOFA score may reflect chronic organ disease (CKD with baseline creatinine 2.5 mg/dL does not represent acute dysfunction), whereas ΔSOFA ≥2 specifically captures new, acute organ failure. Second, prognosis: increasing ΔSOFA over the first 24–48 hours of ICU admission is a strong predictor of 28-day mortality, whereas decreasing ΔSOFA indicates organ recovery and predicts survival. Multiple studies have demonstrated that SOFA trajectory over 48–96 hours is more prognostically informative than any single time-point measurement. Third, treatment response: serial SOFA assessment (typically daily) in ICU patients objectively quantifies the response to interventions such as antibiotics, source control, and resuscitation. Fourth, trial endpoints: organ dysfunction-free days (days alive with SOFA = 0 for each organ component) are increasingly used as primary outcomes in ICU trials as surrogate measures of patient recovery. ΔSOFA between admission and peak value (maximum SOFA) is also used in predictive models for ICU mortality.
• How does SOFA compare to APACHE II? ▼
  SOFA and APACHE II (Acute Physiology and Chronic Health Evaluation II) are both validated ICU severity scores but serve different primary purposes. APACHE II, developed by Knaus et al. in 1985, uses 12 acute physiological variables, age, and chronic health points (total range 0–71) measured in the first 24 hours of ICU admission to predict hospital mortality. APACHE II was designed as a one-time admission assessment for risk stratification and ICU performance benchmarking. SOFA was designed for serial daily measurement to track organ dysfunction over time and is conceptually simpler (6 organ systems, 0–24 total). Comparative performance: both scores predict ICU mortality with similar discrimination (AUROC 0.74–0.82). APACHE II has the advantage of a very large validation database and is widely used for ICU quality benchmarking and clinical trial stratification. SOFA has the advantage of simplicity, direct mapping to organ physiology, and suitability for serial assessment. The Simplified Acute Physiology Score (SAPS-3) is a more modern alternative to APACHE II that includes admission severity and includes contextual factors. In clinical practice, SOFA is most useful for day-to-day tracking of ICU patients' response to treatment and for applying the Sepsis-3 diagnostic criteria. APACHE II is most useful for admission severity adjustment in research and quality improvement programs. Neither should be used as the sole basis for individual clinical decisions or withdrawal of care.
• Should SOFA be calculated daily? ▼
  Yes — daily SOFA calculation is recommended practice in ICU settings by both the Surviving Sepsis Campaign and critical care societies. Serial SOFA assessment provides substantially more clinical information than a single admission score by quantifying the trajectory of organ dysfunction: improving, stable, or worsening. Multiple studies demonstrate that SOFA trajectory is independently associated with 28-day ICU mortality. An improving SOFA (decreasing over 48–72 hours) is associated with significantly better outcomes even in patients with high admission SOFA, while a persistently elevated or rising SOFA despite treatment suggests inadequate source control, antimicrobial failure, or progressive multi-organ failure. Practical frequency: in most ICU settings, SOFA is calculated once daily using morning laboratory values. More frequent assessment (every 12 hours) may be warranted in rapidly changing patients. For the respiratory component, P/F ratio from morning ABG is standard; in patients on non-invasive ventilation or high-flow oxygen, the ROX index (SpO2/FiO2 ÷ RR) has been proposed as an alternative. Electronic health record systems can automate daily SOFA calculation from available laboratory and vital sign data, reducing the documentation burden. Organ dysfunction-free days (SOFA component = 0 for ≥24 hours) are increasingly used as ICU trial endpoints and can be tracked from daily SOFA data. Automatic SOFA alerts have been implemented in some institutions to trigger clinical review when ΔSOFA increases by ≥2.

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