SIRS Criteria Calculator
The Systemic Inflammatory Response Syndrome (SIRS) criteria count four findings (temperature, heart rate, respiratory rate/PaCO₂, white-cell count); two or more define SIRS and, with infection, historically defined sepsis.
Quick answer
The SIRS criteria count four findings — temperature over 38 °C or under 36 °C, heart rate over 90, respiratory rate over 20 (or PaCO₂ under 32), and white-cell count over 12,000, under 4,000, or with over 10% bands. Two or more define the systemic inflammatory response syndrome, which with infection historically defined sepsis.
SIRS criteria
SIRS criteria not met (0–1).
0 of 4 criteria met. SIRS is defined as 2 or more. With a suspected or confirmed infection this historically defined sepsis (ACCP/SCCM 1992); current Sepsis-3 definitions use organ dysfunction, but SIRS remains a widely used screen.
Validated formula
1 point for each criterion met (maximum 4): temperature >38 °C or <36 °C; heart rate >90/min; respiratory rate >20/min or PaCO₂ <32 mmHg; WBC >12,000/µL, <4,000/µL or >10% bands. SIRS is defined as ≥2 criteria present.
Interpretation
- 0–1— SIRS criteria not met.
- ≥2— SIRS present. With a suspected/confirmed source of infection this historically defined sepsis (ACCP/SCCM 1992); evaluate for infection and escalate as clinically indicated.
How to use the SIRS Criteria calculator
- 1Tick the four criteria. Tick abnormal temperature, heart rate over 90, abnormal respiratory rate or PaCO₂, and an abnormal white-cell count or band count.
- 2Read the count. The tool totals how many criteria are met (0–4).
- 3Interpret SIRS. Two or more criteria mean SIRS is present; with a suspected source of infection, evaluate for sepsis and escalate as clinically indicated.
Medical disclaimer: This is general health information, not medical advice. It does not diagnose or treat any condition, and the results are estimates based on public reference formulas. Always consult a qualified doctor about your individual health. If you think you may have a medical emergency, contact your local emergency services immediately.
Talk to a doctor
Get a professional evaluation from a verified doctor by video, audio, or chat — available across 60+ countries on GeraClinic.
Book a consultationFrequently asked questions
Do two SIRS criteria mean I have sepsis?⌄
Not on their own. SIRS (two or more criteria) plus a suspected or confirmed infection historically defined sepsis (ACCP/SCCM 1992). Current Sepsis-3 definitions use organ dysfunction instead, but SIRS is still used as a screen.
Is SIRS still used?⌄
The Sepsis-3 consensus (2016) moved the formal definition of sepsis away from SIRS toward organ dysfunction (a rise in the SOFA score). SIRS remains a quick, widely recognised screening concept.
Can SIRS be present without infection?⌄
Yes. SIRS reflects systemic inflammation, which can also follow trauma, burns, pancreatitis or surgery. The criteria do not establish a cause.
Sources & validation
This calculator reproduces the published SIRS Criteria score, validated for systemic inflammatory response (historical sepsis screen).
Related clinical calculators
Need to discuss a result? Find and book a verified doctor on GeraClinic.