SIRS is the body's systemic inflammatory response to a variety of insults including infection, trauma, burns, pancreatitis, and surgery. It is defined by meeting 2 or more of 4 criteria: abnormal temperature, tachycardia, tachypnea or low PaCO₂, and abnormal WBC count. SIRS with a suspected source of infection was historically called sepsis.

Is SIRS still used in sepsis diagnosis?

The Sepsis-3 definition (2016) replaced SIRS-based sepsis criteria with the SOFA score approach. However, SIRS criteria remain clinically valuable for early detection of inflammatory states and are still used in many hospitals as screening tools. Many studies continue to reference SIRS criteria.

What are the limitations of SIRS?

SIRS criteria are highly sensitive but not specific — many non-infectious conditions trigger SIRS (post-surgical, trauma, pancreatitis). Up to 50% of hospitalized patients may meet SIRS criteria without infection. The high false-positive rate led to the development of qSOFA and SOFA-based definitions for sepsis.

Online Medical Tools — SIRS Criteria

Printed on 2/13/2026

For informational purposes only. This is not medical advice.

Emergency

SIRS Criteria

The Systemic Inflammatory Response Syndrome (SIRS) criteria were defined in 1992 as a set of four clinical findings that indicate a generalized inflammatory process. SIRS is present when two or more criteria are met: temperature >38°C or <36°C, heart rate >90 bpm, respiratory rate >20 or PaCO₂ <32 mmHg, and WBC >12,000 or <4,000 or >10% bands. While Sepsis-3 (2016) moved to SOFA-based definitions, SIRS criteria remain widely referenced and used in many clinical settings for early identification of inflammatory states.

Compare with qSOFA Score

Formula: SIRS = sum of 4 criteria (each 0 or 1). SIRS positive ≥ 2.

Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.