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SIRS, Sepsis, and Septic Shock Criteria

SIRS

Identifies systemic inflammation and helps screen for sepsis risk

All tools /

SIRS, Sepsis, and Septic Shock Criteria

SIRS

Identifies systemic inflammation and helps screen for sepsis risk

SIRS, Sepsis, and Septic Shock Criteria

Defines the severity of sepsis and septic shock.

SIRS Criteria (≥2 meets SIRS definition)

Temperature >38°C (100.4°F) or <36°C (96.8°F)

Yes

Heart rate >90 bpm

Yes

Respiratory rate >20 breaths/min or PaCO2 <32 mmHg

Yes

WBC >12,000/μL or <4,000/μL or >10% bands

Yes

Additional Criteria

Suspected or confirmed infection

Yes

Evidence of organ dysfunction (e.g., SBP <90 mmHg, lactate >2 mmol/L, creatinine >2 mg/dL, bilirubin >2 mg/dL, platelets <100,000/μL, altered mental status)

Select if any organ dysfunction is present

Yes

Persistent hypotension despite adequate fluid resuscitation (requiring vasopressors to maintain MAP ≥65 mmHg)

For septic shock determination

Yes

SIRS: Not Met | Sepsis: No | Severe Sepsis: No | Septic Shock: No

0/7 answered · check to select

Instructions

The Systemic Inflammatory Response Syndrome (SIRS) criteria are used to identify patients with a generalized inflammatory state, often triggered by infection, trauma, or other insults. Clinicians should assess patients for the presence of abnormalities in vital signs and blood counts to determine if the body is exhibiting a systemic response. If two or more SIRS criteria are present, the patient may be at risk for sepsis or another severe inflammatory condition, warranting closer monitoring, further investigations, and early treatment interventions.

Overview

When to use

Why use

Evidences

Interpretation

Number of Criteria Met	Interpretation
<2	Systemic inflammation unlikely
≥2	Meets definition of SIRS; possible sepsis or inflammatory state
≥2 + suspected infection	Suggestive of sepsis; further evaluation required

Systemic Inflammatory Response Syndrome (SIRS) comprises four bedside criteria (temperature, heart rate, respiratory rate, white blood cells) proposed by the 1992 ACCP/SCCM consensus to standardize sepsis terminology; while highly sensitive for infection-related deterioration, SIRS lacks specificity, and Sepsis‑3 (2016) de-emphasized SIRS in favor of organ dysfunction (SOFA/qSOFA), though SIRS remains used in some screening bundles and quality measures.
https://pubmed.ncbi.nlm.nih.gov/1303622/

The 1992 consensus introduced SIRS to capture systemic inflammation from infectious or noninfectious causes, with criteria of temperature >38 or <36°C, heart rate >90, respiratory rate >20 or PaCO2 <32 mmHg, and WBC >12k or <4k or >10% bands; ≥2 criteria indicated SIRS
https://pmc.ncbi.nlm.nih.gov/articles/PMC5418298/

The 2016 task force redefined sepsis as life‑threatening organ dysfunction due to dysregulated host response, operationalized as an acute increase in SOFA ≥2; qSOFA (RR ≥22, SBP ≤100, altered mentation) was proposed for bedside risk stratification outside the ICU.
https://jamanetwork.com/journals/jama/fullarticle/2492881

Meta-analyses show SIRS offers higher sensitivity but lower specificity for predicting mortality than qSOFA, whereas qSOFA has higher specificity but misses more cases; NEWS often outperforms both for early mortality prediction in ED cohorts.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9098353/

Overview

When to use

Why use

Evidences

The SIRS criteria were developed as part of the early definitions of sepsis to provide a framework for recognizing systemic inflammation in hospitalized patients. SIRS is not a diagnosis itself but rather a clinical tool indicating that the body is responding to a significant stressor, which may include infection, trauma, pancreatitis, ischemia, or burns. The criteria involve simple, routinely measured clinical parameters: temperature, heart rate, respiratory rate, and white blood cell count. If two or more of these are abnormal, the patient meets the definition of SIRS.

While originally designed to identify sepsis, SIRS can occur in both infectious and non-infectious conditions. For example, patients with pancreatitis, major trauma, or severe burns may meet SIRS criteria without infection. This lack of specificity has been a key limitation of the tool, leading to the adoption of newer scoring systems such as qSOFA for sepsis risk stratification. However, SIRS remains valuable for its sensitivity in flagging at-risk patients early.

SIRS highlights the importance of recognizing systemic inflammation quickly so clinicians can initiate timely diagnostic testing and interventions. In settings like emergency departments and intensive care units, it provides an early warning sign of potential deterioration. Even though newer definitions of sepsis emphasize organ dysfunction, SIRS continues to be widely taught and used as an educational and clinical screening tool due to its simplicity, accessibility, and sensitivity.

Overview

When to use

Why use

Evidences

Interpretation

Number of Criteria Met	Interpretation
<2	Systemic inflammation unlikely
≥2	Meets definition of SIRS; possible sepsis or inflammatory state
≥2 + suspected infection	Suggestive of sepsis; further evaluation required