SIRS criteria
Systemic inflammatory response syndrome (ACCP/SCCM 1992)
- ACCP/SCCM consensus 1992
Sources last checked: 2026-10-13
SIRS criteria
Systemic inflammatory response syndrome (ACCP/SCCM 1992)
Does not exclude infection or sepsis.
No longer part of the sepsis definition (Sepsis-3, AWMF S3 Sepsis 2025). Many non-infectious conditions — trauma, pancreatitis, burns, exercise — meet the criteria, and one in eight ICU patients with infection and new organ failure meets fewer than two.
Interpretation
| 0–1 — SIRS criteria not met | Does not exclude infection or sepsis. |
|---|---|
| ≥ 2 — SIRS criteria met | Under the 1992 definitions, SIRS plus infection was called sepsis. Since Sepsis-3 (2016) sepsis is defined by organ dysfunction (SOFA rise ≥ 2); SIRS remains a sensitive but unspecific screening signal. |
What is the SIRS criteria?
The SIRS criteria describe a systemic inflammatory response using temperature, heart rate, respiration and white cell count. They were defined at the 1991 ACCP/SCCM consensus conference (Bone, Chest 1992), where two or more criteria plus infection defined sepsis. Sepsis-3 replaced this concept in 2016 with organ dysfunction measured by SOFA.
When to use it
- As a sensitive early warning in emergency triage, often combined with qSOFA.
- Reading older literature and coding rules based on Sepsis-1/-2 definitions.
- Teaching the historical sepsis concept.
When not to use it
- To diagnose sepsis — Sepsis-3 and the German S3 guideline define sepsis via SOFA.
- To judge severity: SIRS does not measure organ dysfunction.
How it is calculated
| Criterion | Points |
|---|---|
| Temperature > 38 °C or < 36 °C | +1 |
| Heart rate > 90 /min | +1 |
| Respiratory rate > 20 /min or PaCO₂ < 32 mmHg (4.3 kPa) | +1 |
| WBC > 12 × 10⁹/L or < 4 × 10⁹/L, or > 10 % immature (band) forms | +1 |
Clinical pearls and limitations
- No longer part of the sepsis definition (Sepsis-3, AWMF S3 Sepsis 2025). Many non-infectious conditions — trauma, pancreatitis, burns, exercise — meet the criteria, and one in eight ICU patients with infection and new organ failure meets fewer than two.
- About half of hospital inpatients meet SIRS at some point, many without infection.
- One in eight ICU patients with infection and new organ failure has fewer than two criteria.
- PaCO₂ < 32 mmHg (4.3 kPa) can substitute for tachypnoea.
- The German S3 guideline 2025 quotes the criteria with '≥'; the 1992 original uses '>' — the difference rarely matters clinically.
Frequently asked questions
How many SIRS criteria are needed?
Two or more of the four criteria.
Is SIRS still used for sepsis?
Not for the definition. Since Sepsis-3 (2016) sepsis requires organ dysfunction; SIRS remains a screening signal.
Why is SIRS considered unspecific?
Trauma, surgery, pancreatitis, burns or simple exertion can fulfil the criteria without any infection.
Evidence and guidelines
- Primary source: Bone RC, Balk RA, Cerra FB et al. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. Chest 1992;101(6):1644-1655.
- Singer M et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA 2016;315(8):801-810.
- Deutsche Sepsis-Gesellschaft. S3-Leitlinie Sepsis – Prävention, Diagnose, Therapie und Nachsorge, Update 2025 (AWMF-Register 079-001), Definition 1.
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