SIRS vs qSOFA

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Two tools help clinicians recognize it early at the bedside: SIRS (Systemic Inflammatory Response Syndrome) and qSOFA (quick Sequential Organ Failure Assessment).

SIRS Criteria

SIRS identifies a generalized inflammatory state. A patient meets SIRS if they have ≥ 2 of the following:

• Temperature > 38°C (100.4°F) or < 36°C (96.8°F)
• Heart rate > 90 bpm
• Respiratory rate > 20/min or PaCO₂ < 32 mmHg
• WBC > 12,000 or < 4,000, or > 10% bands

SIRS is sensitive but not specific—many non-infectious conditions (trauma, pancreatitis, surgery) can trigger SIRS.

qSOFA Criteria

qSOFA was introduced in Sepsis-3 to better predict poor outcomes in suspected infection. One point for each:

• Respiratory rate ≥ 22/min
• Altered mental status (GCS < 15)
• Systolic blood pressure ≤ 100 mmHg

A qSOFA score of ≥ 2 suggests increased risk of death or prolonged ICU stay and should prompt further evaluation for sepsis.

Which Should You Use?

SIRS is useful as a broad screening tool to identify patients who might have infection-related inflammation. qSOFA is better at predicting which of those patients are at highest risk of deterioration. In practice, many clinicians use both: SIRS to cast a wide net, and qSOFA to triage severity.

Use our SIRS calculator and qSOFA calculator side by side.