What are the criteria for diagnosing sepsis (Systemic Inflammatory Response Syndrome)?

From the Guidelines

Sepsis Diagnosis Criteria

Sepsis is diagnosed based on a suspected or documented infection, in conjunction with organ dysfunction, which may be indicated by a Sequential Organ Failure Assessment (SOFA) score of 2 or more 1.

• The criteria include:
  • A suspected or documented infection
  • At least two of three clinical abnormalities, including:
    • Glasgow coma score of 14 or less
    • Systolic blood pressure of 100 mmHg or less
    • Respiratory rate 22/min or greater
  • Organ dysfunction, which may be indicated by a SOFA score of 2 or more 1
  • Serum lactate levels greater than 2 mmol/L in the absence of hypovolemia may also be used to identify sepsis 1

Key Diagnostic Factors

The diagnosis of sepsis is based on the presence of a suspected or documented infection, along with signs of organ dysfunction, such as an increased SOFA score or elevated serum lactate levels 1.

• Infection: A suspected or documented infection is a key criterion for diagnosing sepsis 1.
• Organ Dysfunction: Organ dysfunction, as indicated by a SOFA score of 2 or more, is a critical factor in diagnosing sepsis 1.
• Serum Lactate: Elevated serum lactate levels, greater than 2 mmol/L, in the absence of hypovolemia, may also be used to identify sepsis 1.

From the Research

Criteria for Diagnosing Sepsis

The criteria for diagnosing sepsis, also known as Systemic Inflammatory Response Syndrome (SIRS), have been defined and updated in various studies. The key criteria include:

• Life-threatening organ dysfunction due to a dysregulated host response to infection 2, 3
• Increase in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score of 2 points or more, which is associated with an in-hospital mortality greater than 10% 3
• Presence of at least 2 of the following clinical criteria: respiratory rate of 22/min or greater, altered mentation, or systolic blood pressure of 100 mm Hg or less, which together constitute a new bedside clinical score termed quickSOFA (qSOFA) 3

Comparison of Sepsis Scoring Systems

Various studies have compared the efficacies of different sepsis scoring systems, including:

• SOFA score: yielded the best result with an "area under the curve" (AUC) of the "receiver operating characteristic" (ROC) curve of 0.868 4
• qSOFA score: had a predictive validity for in-hospital mortality that was statistically greater than SIRS, but lower than SOFA 2, 5
• SIRS criteria: had a lower predictive validity for in-hospital mortality compared to SOFA and qSOFA 2, 6, 5, 4

Clinical Application

The updated definitions and clinical criteria for sepsis should replace previous definitions and offer greater consistency for epidemiologic studies and clinical trials 3. The use of qSOFA score as a prompt to consider possible sepsis, especially in out-of-hospital, emergency department, or general hospital ward settings, is supported by the evidence 2, 3. However, the low sensitivity of qSOFA score may diminish its clinical utility for patients with suspected infection in the emergency department 5.