Systemic inflammatory response syndrome (SIRS) criteria were used to define sepsis from 1991 to 2016. Sepsis-3 now defines sepsis as life-threatening organ dysfunction due to infection (SOFA increase ≥ 2), but SIRS remains a sensitive screening tool used in many hospitals.
How to use the Sepsis Calculator
- Temperature above 38 °C or below 36 °C
- Heart rate above 90 bpm
- Respiratory rate above 20/min or PaCO₂ below 32 mmHg
- WBC above 12,000 or below 4,000/µL, or more than 10% bands
- Suspected or confirmed infection
- New organ dysfunction or hypotension
Results update as you type, and every field accepts the units shown in its menu.
How it works
Each answer carries the points shown in the published score. The calculator adds them up and maps the total to the published interpretation.
Scoring table
| Item | Answers and points |
|---|---|
| Temperature above 38 °C or below 36 °C | No = 0; Yes = 1 |
| Heart rate above 90 bpm | No = 0; Yes = 1 |
| Respiratory rate above 20/min or PaCO₂ below 32 mmHg | No = 0; Yes = 1 |
| WBC above 12,000 or below 4,000/µL, or more than 10% bands | No = 0; Yes = 1 |
| Suspected or confirmed infection | No = 0; Yes = 1 |
| New organ dysfunction or hypotension | No = 0; Yes = 1 |
Inputs explained
| Field | What to enter |
|---|---|
| Temperature above 38 °C or below 36 °C | Choose one: No, Yes |
| Heart rate above 90 bpm | Choose one: No, Yes |
| Respiratory rate above 20/min or PaCO₂ below 32 mmHg | Choose one: No, Yes |
| WBC above 12,000 or below 4,000/µL, or more than 10% bands | Choose one: No, Yes |
| Suspected or confirmed infection | Choose one: No, Yes |
| New organ dysfunction or hypotension | Choose one: No, Yes |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Score = sum of the points for each item
Worked example
Inputs — Temperature above 38 °C or below 36 °C: Yes; Heart rate above 90 bpm: Yes; Respiratory rate above 20/min or PaCO₂ below 32 mmHg: No; WBC above 12,000 or below 4,000/µL, or more than 10% bands: No; Suspected or confirmed infection: Yes; New organ dysfunction or hypotension: No.
Results — SIRS criteria met = 2 of 4; Screen = Possible sepsis – assess for organ dysfunction (SOFA).
Key terms
- SIRS
- Systemic inflammatory response syndrome.
Frequently asked questions
What are the SIRS criteria?
Temperature, heart rate, breathing rate/PaCO₂ and white cell count; 2 or more is SIRS.
What is the current sepsis definition?
Sepsis-3: life-threatening organ dysfunction (SOFA rise ≥ 2) caused by infection.
What should happen if sepsis is suspected?
Rapid antibiotics, cultures, lactate and fluids according to the hour-1 bundle.