Doctors use the sequential organ failure assessment (SOFA) score, previously known as the sepsis-related organ failure assessment, to measure a person’s organ function or failure rate.

SOFA is a scoring system that helps medical professionals evaluate how different organ systems are performing. Healthcare professionals can use it to track a person’s status during a stay in an intensive care unit (ICU) and estimate the risk of complications.

Read on to learn more about the SOFA score, its uses, and how doctors calculate it.

A person in the ICU-1.Share on Pinterest
skaman306/Getty Images

The SOFA score is a scoring system that helps doctors evaluate how well the organs and systems in the body are functioning. It assesses the respiratory, cardiovascular, hepatic, renal, hematological, and neurological systems and assigns a score of 0–4 depending on the data in each category.

The United States Department of Health and Human Services (HHS) notes that the higher the SOFA score, the higher the risk of death.

According to a 2023 study, medical professionals developed the SOFA score in 1996 to provide a simple method of assessing and monitoring organ dysfunction. It was originally known as the sepsis-related organ failure assessment score.

Sepsis is a life threatening medical emergency due to the body’s dramatic response to an infection. In the United States, sepsis affects about 1.7 million adults and causes 350,000 deaths each year.

However, medical experts changed the name of the scoring system, as it was also applicable to those without sepsis. Today, the SOFA score is one of the most common scoring systems in adult intensive care in clinical practice and research.

Medical professionals can use the SOFA score for the following:

  • Assessing acute morbidity: Using six common data points, a doctor can calculate the risk of death following a critical illness.
  • Defining therapeutic response in clinical trials: Researchers can use a SOFA score to determine the effectiveness of novel therapies in trials.
  • Diagnosing sepsis syndrome at an individual patient level: The SOFA score is one of the diagnostic criteria for sepsis syndrome. Its precise and consistent assessment allows doctors to deliver timely interventions.

Below is a table showing how doctors use data from organ system parameters to calculate the SOFA score:

ParametersScore 0Score 1Score 2Score 3Score 4
Respiratory system
PaO2/FiO2 in millimeters of mercury (mmHg)		> 400< 400< 300< 200 with respiratory support< 100 with respiratory support
Nervous system
Glasgow coma scale		1513–1410–126–9< 6
Cardiovascular system
Mean arterial pressure (MAP)		MAP > 70 mmHgMAP < 70 mm/Hgdopamine ≤ 5 micrograms per kilogram per minute (μg/kg/min)dopamine > 5 μg/kg/mindopamine > 15 μg/kg/min
Liver
Bilirubin miligrams per deciliter (mg/dL) or micromole per liter [μmol/L]		< 1.2 [< 20]1.2–1.9 [20–32]2.0–5.9 [33–101]6.0–11.9 [102–204]> 12.0 [> 204]
Coagulation
Platelets ×103/mL		> 150< 150< 100< 50< 20
Kidney
Creatinine (mg/dL) [μmol/L]		< 1.2 [< 110]1.2–1.9 [110–170]2.0–3.4 [171–299]3.5–4.9 [300–440]> 5.0 [> 440]

A doctor will assign a score ranging from 0–4 for each organ system. After adding the score for the six parameters, a person may have a score ranging from 0 to a maximum of 24.

A medical professional will calculate this score every 24 hours while a person is on admission until discharge. They may calculate the score individually for each organ or as a sum of scores during a single ICU admission within 24 hours.

A person with a SOFA score of 2 may have a high chance of survival, while a score greater than 11 suggests a very low chance of survival.

The quick SOFA (qSOFA) score is a simple bedside prompt that helps clinicians identify patients with suspected infections at a greater risk of poor outcomes outside the ICU.

Healthcare professionals calculate the qSOFA score by assigning one point to the following diagnostic criteria:

  • low blood pressure, which is a systolic blood pressure (SBP) of 100 mmHg or less
  • high respiratory rate, which is a respiratory rate of 22 breaths per minute or more
  • altered mentation, which is a Glasgow coma scale (GCS) score of less than 15

The score ranges from 0–3 points. A qSOFA score of 2 or more is associated with a greater risk of death or prolonged ICU stay. A qSOFA score can provide a simpler and easier assessment of evaluating a patient’s health outcome than the SOFA score, which requires multiple laboratory tests.

The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) recommends using the qSOFA score as a simple prompt to identify infected patients outside the ICU who are likely to be septic.

The sequential organ failure assessment, or SOFA, score is a rating system that medical professionals use to assess a person’s organ function or organ failure rate following a stay in the ICU. The higher a person’s SOFA score, the greater their risk of death.

Originally known as the sepsis-related organ failure assessment, medical professionals found the SOFA score helpful in evaluating critically ill people without sepsis. For this reason, they changed the name to the sequential organ failure assessment.

A medical professional will calculate this score every 24 hours while a person is on admission until discharge. They will assign a score between 0–4 for 6 different organ systems. They may calculate the score individually for each organ or as a sum of scores during a single ICU admission.