emergency & critical carescoring tool

SOFA Score (Sequential Organ Failure Assessment)

SOFA quantifies multi-organ dysfunction across 6 systems (respiration, coagulation, liver, cardiovascular, CNS, renal), each scored 0–4. Total score ranges 0–24. It is the cornerstone of the Sepsis-3 definition: sepsis = suspected infection + acute SOFA increase ≥2.

inputs

E.g., PaO₂ 80 on FiO₂ 0.4 = 200
mmHg
mmHg
Optional — used for renal component if available

✓ when to use

Use in ICU and acute care settings to quantify organ dysfunction severity, track organ failure trajectory, and define sepsis (Sepsis-3). Calculate at ICU admission and daily thereafter. An acute SOFA increase ≥2 points from baseline in a patient with suspected infection constitutes sepsis.

✗ when not to use

SOFA requires laboratory values and vasopressor data that may not be immediately available outside ICU. For bedside screening outside ICU, use qSOFA. SOFA assumes a baseline of 0 for patients without known pre-existing organ dysfunction — in patients with chronic organ failure (e.g., CKD, cirrhosis), the acute CHANGE in SOFA is what matters, not the absolute score.

clinical pearls

  • Sepsis-3 definition: suspected infection + acute SOFA ≥2 increase from baseline. Septic shock: sepsis + vasopressors required to maintain MAP ≥65 + lactate >2 mmol/L despite adequate resuscitation.
  • For patients without known pre-existing organ dysfunction, baseline SOFA is assumed to be 0. For patients with chronic organ dysfunction, you need to know their baseline to calculate the acute change.
  • The cardiovascular component uses vasopressor dose ranges, not just MAP. A patient on high-dose noradrenaline with MAP 70 still scores 3–4 on the cardiovascular component.
  • SOFA is a DAILY assessment in ICU — trends matter more than single values. A rising SOFA trajectory despite treatment indicates clinical deterioration and should prompt re-evaluation of the management plan.
  • The PaO₂/FiO₂ ratio is the respiratory component. Quick estimation: PaO₂ (mmHg) / FiO₂ (as decimal). On room air (FiO₂ 0.21), normal PaO₂ ~95 gives PF ~450. On 40% O₂ (FiO₂ 0.4), PaO₂ of 80 gives PF = 200.

related tools

qsofaBedside screening outside ICUnews2UK early warning scoregcsCNS component of SOFA