Quick answer: There is no single “normal” SOFA score — a score of 0 in each organ system is the baseline (no dysfunction). A total SOFA score ≥2 above baseline meets the Sepsis-3 organ dysfunction criterion. Scores above 11 carry ICU mortality exceeding 50%. Use our free SOFA score calculator to compute the full score across all 6 organ systems instantly.
What Is the SOFA Score?
The Sequential Organ Failure Assessment (SOFA) score is a validated clinical scoring system used in the ICU to quantify the degree of organ dysfunction across six physiological systems: respiratory, coagulation, liver, cardiovascular, neurological, and renal. It was originally developed by Vincent et al. in 1996 under the auspices of the European Society of Intensive Care Medicine (ESICM).
Critically, the SOFA score was designed to describe organ dysfunction over time — not solely to predict mortality. Its power lies in serial measurement: tracking whether organ function is improving, stable, or deteriorating in response to treatment.
Why the SOFA Score Matters — Two Critical Applications
- Sepsis-3 criterion: The 2016 Third International Consensus Definitions for Sepsis (Sepsis-3) redefined sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection. The operational criterion is a suspected infection plus an acute increase in SOFA score of ≥2 points from baseline.
- ICU prognostication: Serial SOFA scores — particularly the trajectory over the first 96 hours — are strongly associated with ICU mortality, with rising scores indicating dramatically worsening prognosis.
How to Calculate the SOFA Score — All 6 Systems
Each organ system is scored 0–4, with 0 representing normal function and 4 representing the most severe dysfunction. Maximum total = 24 points.
1. Respiratory — PaO₂/FiO₂ Ratio (P/F Ratio)
| Score | PaO₂/FiO₂ (mmHg) | Clinical context |
|---|---|---|
| 0 | ≥400 | Normal oxygenation |
| 1 | 300–399 | Mild hypoxaemia |
| 2 | 200–299 | Moderate hypoxaemia |
| 3 | 100–199 with respiratory support | Severe — ARDS range |
| 4 | <100 with respiratory support | Critical — severe ARDS |
Clinical note: Scores of 3 and 4 require the patient to be on respiratory support (mechanical ventilation or CPAP). If PaO₂ is unavailable, SpO₂/FiO₂ ratio can be substituted using validated conversion tables.
2. Coagulation — Platelet Count (×10³/μL)
| Score | Platelets |
|---|---|
| 0 | ≥150 |
| 1 | 100–149 |
| 2 | 50–99 |
| 3 | 20–49 |
| 4 | <20 |
3. Liver — Bilirubin (mg/dL)
| Score | Bilirubin (mg/dL) | Bilirubin (μmol/L) |
|---|---|---|
| 0 | <1.2 | <20 |
| 1 | 1.2–1.9 | 20–32 |
| 2 | 2.0–5.9 | 33–101 |
| 3 | 6.0–11.9 | 102–204 |
| 4 | ≥12.0 | >204 |
4. Cardiovascular — Mean Arterial Pressure / Vasopressors
| Score | Cardiovascular Status |
|---|---|
| 0 | MAP ≥70 mmHg |
| 1 | MAP <70 mmHg |
| 2 | Dopamine <5 μg/kg/min OR Dobutamine (any dose) |
| 3 | Dopamine 5–15 μg/kg/min OR Epinephrine ≤0.1 OR Norepinephrine ≤0.1 μg/kg/min |
| 4 | Dopamine >15 μg/kg/min OR Epinephrine >0.1 OR Norepinephrine >0.1 μg/kg/min |
Note: This is the cardiovascular component most frequently updated in practice. Current evidence suggests this component has lower mortality prediction weight than other components at equivalent scores — a key limitation of the original SOFA.
5. Neurological — Glasgow Coma Scale (GCS)
| Score | GCS |
|---|---|
| 0 | 15 |
| 1 | 13–14 |
| 2 | 10–12 |
| 3 | 6–9 |
| 4 | <6 |
Important: In sedated patients, the GCS may be artificially suppressed. Document sedation status alongside SOFA scoring. This is a known confound, particularly in mechanically ventilated patients receiving continuous sedation.
6. Renal — Creatinine (mg/dL) or Urine Output
| Score | Creatinine (mg/dL) | Urine Output |
|---|---|---|
| 0 | <1.2 | — |
| 1 | 1.2–1.9 | — |
| 2 | 2.0–3.4 | — |
| 3 | 3.5–4.9 | <500 mL/day |
| 4 | ≥5.0 | <200 mL/day |
Research consistently shows that creatinine is the single most powerful individual SOFA component for mortality prediction in multivariate analysis.
SOFA Score Interpretation — Mortality by Score Range
| Total SOFA Score | Estimated ICU Mortality | Clinical Significance |
|---|---|---|
| 0–6 | <10% | Low organ dysfunction; most patients recover |
| 7–9 | 15–20% | Moderate dysfunction; close monitoring required |
| 10–12 | 40–50% | Significant organ failure; high-level intervention |
| 13–14 | 50–60% | Severe failure across multiple systems |
| 15+ | >80% | Critical — very high mortality risk |
Critical caveat: These mortality estimates are population-level probabilities. Individual prognosis depends on the underlying diagnosis, trajectory of the score, patient age, comorbidities, and quality of ICU care. Never use the SOFA score as a sole determinant of treatment limitation decisions.
What Is a “Normal” SOFA Score?
There is no “normal” SOFA score in the way there is a normal blood pressure. The baseline is 0 for each organ system — meaning no detectable dysfunction. A total score of 0 represents a patient with no organ system impairment across all six parameters.
In practice, many ICU patients have some baseline organ impairment before the acute illness (e.g., chronic kidney disease with an elevated creatinine). For these patients, the delta SOFA — the change from their individual baseline — is more clinically informative than the absolute score.
Delta SOFA — The Most Clinically Important Concept
The trajectory of SOFA over time is more prognostically powerful than any single measurement. Three key patterns:
- Decreasing SOFA (first 96 hours): ICU mortality <27% — organs responding to treatment
- Stable SOFA (first 96 hours): ICU mortality 28–46% — partial response
- Increasing SOFA (first 96 hours): ICU mortality >50% — treatment-refractory organ failure
This is why the SOFA score should be calculated at ICU admission and then every 24–48 hours rather than as a one-time measurement.
SOFA Score and Sepsis-3
The Third International Consensus Definitions for Sepsis and Septic Shock (Singer et al., JAMA 2016) established SOFA as the operational definition of organ dysfunction in sepsis:
- Sepsis: Suspected or confirmed infection + acute SOFA increase of ≥2 points from baseline
- Septic shock: Sepsis + vasopressor requirement to maintain MAP ≥65 mmHg + serum lactate >2 mmol/L despite adequate fluid resuscitation
A baseline SOFA of 0 is assumed for patients without pre-existing organ dysfunction. The ≥2 point threshold corresponds to an approximate 10% in-hospital mortality risk in the general hospital population with suspected infection.
qSOFA — The Bedside Screening Tool
The quick SOFA (qSOFA) was introduced alongside Sepsis-3 as a rapid bedside screening tool requiring no laboratory values. Score 1 point each for:
- Respiratory rate ≥22 breaths/min
- Altered mentation (GCS <15)
- Systolic BP ≤100 mmHg
A qSOFA score of ≥2 should prompt clinicians to investigate for organ dysfunction and consider ICU admission. It does not replace the full SOFA score for diagnosing sepsis.
SOFA Limitations to Know
- Sedation confounds GCS. Mechanically ventilated patients receiving sedation will score higher on the neurological component regardless of true neurological status.
- Cardiovascular component underweights mortality. Large registry data shows cardiovascular organ failure at equivalent scores predicts lower mortality than other SOFA components.
- Not validated in children. Paediatric SOFA (pSOFA) exists but the standard SOFA is validated for adults only.
- Chronic disease confounds baseline. Patients with CKD, cirrhosis, or chronic respiratory failure have elevated baseline scores that must be accounted for.
- SOFA 2.0 in development. A modernised version (SOFA 2.0) incorporating updated ICU practice and EHR integration was in validation as of 2025.
Free SOFA Score Calculator
Calculate SOFA score across all 6 organ systems instantly with our free SOFA score calculator. Includes Sepsis-3 organ dysfunction threshold, mortality prediction by score range, and EMR documentation template. No login required.
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Frequently Asked Questions
What SOFA score indicates sepsis?
Per the Sepsis-3 definition (Singer et al., JAMA 2016), an acute increase in SOFA score of ≥2 points from baseline in a patient with suspected infection meets the operational criterion for sepsis. This applies regardless of total SOFA score — it is the acute change that matters.
What SOFA score is associated with high mortality?
SOFA scores above 11 are associated with ICU mortality exceeding 50%. Scores above 15 carry mortality rates above 80%. However, trajectory matters as much as the absolute value — a rising SOFA over 96 hours is a stronger mortality predictor than a static high score.
How often should SOFA be calculated in the ICU?
At ICU admission and then every 24–48 hours. The first 96-hour trajectory is the most prognostically significant window. Serial calculation at fixed intervals allows objective tracking of organ recovery or deterioration.
Can SOFA be used to limit treatment?
The SOFA score should inform but not solely determine treatment limitation decisions. A high SOFA reflects population-level risk — individual patient factors, clinical trajectory, patient values, and family discussion must all be integrated into any treatment limitation decision.
What is the difference between SOFA and APACHE II?
APACHE II is calculated once at ICU admission and uses 12 physiological variables plus age and chronic health points — it was designed for mortality prediction at admission. SOFA is calculated serially throughout the ICU stay and was designed to track organ dysfunction over time. SOFA is more useful for monitoring treatment response; APACHE II for admission severity stratification.
References
- Vincent JL, Moreno R, Takala J, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. Intensive Care Med. 1996;22(7):707-710. PMID: 8844239.
- Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801-810. PMID: 26903338.
- Ferreira FL, Bota DP, Bross A, Mélot C, Vincent JL. Serial evaluation of the SOFA score to predict outcome in critically ill patients. JAMA. 2001;286(14):1754-1758. PMID: 11594901.
- Raith EP, Udy AA, Bailey M, et al. Prognostic accuracy of the SOFA score, SIRS criteria, and qSOFA score for in-hospital mortality among adults with suspected infection admitted to the intensive care unit. JAMA. 2017;317(3):290-300. PMID: 28114553.
- Lambden S, Laterre PF, Levy MM, Francois B. The SOFA score — development, utility and challenges of accurate measurement in clinical trials. Crit Care. 2019;23(1):374. PMID: 31775846.
Written by Nikhil Mahajan, PT, MPT | Last reviewed: May 2026 | Free SOFA Score Calculator →