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emergency-medicine critical-care infectious-disease

SIRS Criteria and Sepsis Definition

Identifies systemic inflammatory response syndrome (SIRS) and sepsis. Two or more SIRS criteria with suspected infection = sepsis (Sepsis-2 definition).

Used in: Sepsis

Score interpretation

SIRS not met

→ No SIRS; investigate for other causes of symptoms

SIRS (2+ criteria)

→ SIRS present; if infection suspected = Sepsis; start Sepsis-6 bundle within 1 hour

SIRS + infection (Sepsis)

→ Sepsis: blood cultures, broad-spectrum antibiotics, fluids, lactate, urine output; reassess for organ dysfunction (qSOFA/SOFA)

Full SIRS + infection confirmed

→ Sepsis with all SIRS criteria and confirmed infection; urgent sepsis bundle; assess for septic shock (MAP <65 after 30mL/kg fluids)

Interpretation bands for the SIRS / Sepsis. Apply clinical judgement and local guidance.

References

Related

Curated clinical cross-links plus same-class fallbacks.

📚 MRCEM Revision

Featured in these MRCEM clinical pathways

The SIRS / Sepsis is covered in detail — with RCEM/NICE evidence base, indications and pitfalls — in the following exam-focused pathways on our sister siteReviseMRCEM.

MRCEM Primary / Intermediate / OSCE candidates: each pathway includes exam-style questions, RCEM/NICE citations, and FAQ summaries.

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.