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Sofa Score Calculator (Sequential Organ Failure Assessment)

SOFA score calculator assessing six organ systems — respiratory, coagulation, liver, cardiovascular, neurological, and renal — to estimate ICU mortality risk.

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Inputs

Respiratory (PaO₂/FiO₂ ratio, mmHg)

Coagulation (Platelets, ×10³/µL)

Liver (Bilirubin, mg/dL)

Cardiovascular (MAP or vasopressors)

Neurological (Glasgow Coma Scale)

Renal (Creatinine, mg/dL or Urine Output)

SOFA Score

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Get a plain-English breakdown of your result with practical next steps.

SOFA Score—points

The formula

How the
result is
computed.

What Is the SOFA Score?

The Sequential Organ Failure Assessment (SOFA) score is a validated clinical tool used in intensive care units (ICUs) to quantify the degree of organ dysfunction across six physiological systems. Originally developed by Vincent et al. in 1996 and subsequently refined by the Sepsis-3 Task Force (Singer et al., JAMA 2016), the SOFA score has become the international standard for assessing sepsis severity and predicting ICU mortality. A total score is produced by summing one sub-score per organ system, each graded 0 (normal) to 4 (most severe dysfunction). The underlying principle of SOFA is that sepsis represents a dysregulated host response to infection characterized by life-threatening organ dysfunction—a cascade of failures that the SOFA score quantifies objectively using bedside and laboratory parameters.

The SOFA Formula

The total SOFA score equals the sum of six independent organ sub-scores:

SOFA = S_resp + S_coag + S_liver + S_cardio + S_cns + S_renal

The maximum possible total is 24, representing failure across every assessed system. Clinicians calculate the score at ICU admission and repeat it every 24 hours using the worst values observed in each period. Per Sepsis-3 criteria, an acute SOFA increase of 2 or more points from baseline defines life-threatening organ dysfunction consistent with sepsis. The six-organ focus reflects the systems most vulnerable to sepsis-induced hypoperfusion and inflammation: the lungs (oxygenation), blood coagulation cascade, liver (synthetic and detoxification function), cardiovascular system (perfusion), central nervous system (encephalopathy), and kidneys (filtration and fluid regulation). Each organ's sub-score captures the severity of dysfunction independent of others, allowing clinicians to identify which systems require priority intervention.

Component Scoring Tables

1. Respiratory — PaO₂/FiO₂ Ratio (mmHg)

Score 0: ≥ 400 mmHg
Score 1: 300–399 mmHg
Score 2: 200–299 mmHg
Score 3: 100–199 mmHg with mechanical ventilation
Score 4: < 100 mmHg with mechanical ventilation

2. Coagulation — Platelets (×10³/µL)

Score 0: ≥ 150
Score 1: 100–149
Score 2: 50–99
Score 3: 20–49
Score 4: < 20

3. Liver — Bilirubin (mg/dL)

Score 0: < 1.2
Score 1: 1.2–1.9
Score 2: 2.0–5.9
Score 3: 6.0–11.9
Score 4: ≥ 12.0

4. Cardiovascular — MAP or Vasopressors

Score 0: MAP ≥ 70 mmHg, no vasopressors
Score 1: MAP < 70 mmHg
Score 2: Dopamine ≤ 5 µg/kg/min or dobutamine (any dose)
Score 3: Dopamine 5.1–15 µg/kg/min, or epinephrine/norepinephrine ≤ 0.1 µg/kg/min
Score 4: Dopamine > 15 µg/kg/min, or epinephrine/norepinephrine > 0.1 µg/kg/min

Vasopressor doses must be sustained for at least 1 hour to qualify for scoring.

5. Neurological — Glasgow Coma Scale (GCS)

Score 0: GCS 15
Score 1: GCS 13–14
Score 2: GCS 10–12
Score 3: GCS 6–9
Score 4: GCS < 6

6. Renal — Creatinine (mg/dL) or Urine Output

Score 0: Creatinine < 1.2 mg/dL
Score 1: 1.2–1.9 mg/dL
Score 2: 2.0–3.4 mg/dL
Score 3: 3.5–4.9 mg/dL or urine output < 500 mL/day
Score 4: ≥ 5.0 mg/dL or urine output < 200 mL/day

Use the worst value — creatinine or urine output — recorded in the prior 24 hours.

Interpreting the Total SOFA Score

Mortality benchmarks established by peer-reviewed research (PMC, 2023) and the Sepsis-3 consensus (Singer et al., JAMA 2016) associate total scores with the following ICU mortality rates:

0–6: Mortality below 10%
7–9: Approximately 15–20% mortality
10–12: Approximately 40–50% mortality
13–14: Approximately 50–60% mortality
≥ 15: Greater than 80% mortality

The delta SOFA — the change in score over 24–48 hours — carries independent prognostic weight: a rising score signals deterioration and correlates with increased mortality risk, while a declining score indicates positive treatment response and improved organ function. The ASPR TRACIE fact sheet highlights delta SOFA as a critical reassessment tool during mass-casualty and pandemic resource-allocation scenarios. Experienced ICU teams monitor serial SOFA values to assess treatment efficacy, guide therapeutic escalation or de-escalation, and inform prognostic discussions with families.

Clinical Applications

The SOFA score calculator supports ICU triage, ventilator and vasopressor management, sepsis diagnosis per Sepsis-3 criteria, clinical trial patient stratification, and crisis standards of care during resource-limited events. It is particularly valuable in tracking longitudinal organ dysfunction and predicting patient trajectory when integrated with other severity scoring systems such as APACHE III or SAPS III. Results must always be interpreted alongside full clinical assessment, patient history, comorbidities, and multidisciplinary team review. The SOFA score is a decision-support instrument and does not replace individualized clinical judgment.

Reference

Frequently asked questions

What is a normal SOFA score?

A SOFA score of 0 indicates completely normal organ function across all six assessed systems. Scores from 0 to 6 are generally associated with ICU mortality below 10%. In clinical practice, a baseline of 0 in a non-critically ill patient is considered normal, while any acute increase of 2 or more points in a suspected infection context signals organ dysfunction requiring immediate evaluation and intervention.

What SOFA score indicates sepsis?

Per the Sepsis-3 definition (Singer et al., JAMA 2016), sepsis is identified by an acute increase in total SOFA score of 2 or more points from the patient's baseline, occurring alongside a suspected infection. This threshold reflects life-threatening organ dysfunction. For patients without known prior organ impairment, a baseline SOFA of 0 is assumed, so any score of 2 or above meets the diagnostic threshold for sepsis.

What does a SOFA score of 11 mean?

A SOFA score of 11 falls in the 10–12 range, which clinical research associates with approximately 40–50% ICU mortality. At this severity, a patient typically exhibits dysfunction across multiple systems — for example, a PaO₂/FiO₂ ratio below 200 mmHg on mechanical ventilation, a platelet count under 50,000/µL, bilirubin above 6 mg/dL, or creatinine exceeding 3.5 mg/dL. Aggressive, continuous monitoring and intervention are essential at this score level.

How is SOFA score different from qSOFA?

The SOFA score evaluates six organ systems using laboratory values — arterial blood gas, platelet count, bilirubin, creatinine, GCS, and hemodynamics — making it highly accurate but resource-intensive. The quick SOFA (qSOFA) uses only three bedside parameters: altered mentation, respiratory rate ≥ 22 breaths/min, and systolic BP ≤ 100 mmHg. A qSOFA score of 2 or more prompts full SOFA evaluation. SOFA is significantly more sensitive and specific for predicting ICU mortality than qSOFA alone.

Can the SOFA score be used outside the ICU?

Although SOFA was originally designed for ICU settings, Sepsis-3 guidelines recommend applying it whenever sepsis is clinically suspected, including in emergency departments and general hospital wards. Obtaining all required laboratory values — particularly an arterial blood gas for PaO₂/FiO₂ — may not be feasible in every setting. When full data are unavailable, qSOFA functions as the practical first-line screening tool, with complete SOFA assessment performed once laboratory results become available.

How often should the SOFA score be recalculated in the ICU?

ICU clinicians typically recalculate the SOFA score every 24 hours, always using the worst values recorded within each 24-hour window. Serial calculations produce the delta SOFA, the change in score over time, which independently predicts outcomes: an increase of 1 or more points over 24–48 hours correlates with significantly higher mortality. Many ICU protocols also trigger unscheduled recalculation after major clinical events such as vasopressor initiation, intubation, or acute hemodynamic deterioration.