SIRS Criteria Attribute
Temperature >38°C (option d) is an attribute of the SIRS criteria. 1
Understanding SIRS Criteria
The Systemic Inflammatory Response Syndrome (SIRS) is defined by the presence of at least 2 of the following 4 criteria: 1
- Temperature >38°C or <36°C 1
- Heart rate >90 beats/min 1
- Respiratory rate >20 breaths/min (or PaCO2 <32 mmHg) 1
- White blood cell count >12,000/mm³ or <4,000/mm³ or >10% immature forms 1
Why the Other Options Are Incorrect
Altered mental status (option a) is not a SIRS criterion—it is instead a criterion for end-organ injury used in diagnosing severe sepsis or maternal sepsis. 2 In the context of maternal sepsis, altered mental status (agitation, confusion, or unresponsiveness) serves as one of the diagnostic criteria for severe sepsis, not for the initial SIRS screening. 2
Systolic blood pressure <100 mmHg (option b) is not part of SIRS criteria. Hypotension is a criterion for septic shock or severe sepsis with end-organ injury. 2 In pregnant women (20 weeks gestation through 3 days postpartum), the modified threshold is SBP <85 mmHg for diagnosing end-organ injury. 2
Oxygen saturation <90% on room air (option c) is not a SIRS criterion. This represents respiratory failure and would be considered evidence of end-organ injury in the diagnosis of severe sepsis. 2
Important Context for Pregnancy
In pregnant women, the obstetrically modified SIRS (omSIRS) criteria are recommended by the California Maternal Quality Care Collaborative for sepsis screening. 2, 3 The omSIRS maintains the same four basic parameters as standard SIRS but with modified thresholds: 3
- Temperature >38°C or <36°C (unchanged)
- Heart rate >100 beats/min (modified from >90)
- Respiratory rate >20 breaths/min (unchanged)
- WBC >12,000 or <4,000 cells/μL or >10% bands (unchanged)
Critical caveat: Normal physiologic changes in pregnancy cause significant overlap with SIRS criteria, particularly for heart rate, respiratory rate, and white blood cell count. 4 Studies show that 72% of immediate postpartum women meet SIRS criteria despite only 1.25% having actual sepsis, demonstrating poor specificity in this population. 5 This is why the three-stage screening approach combining omSIRS with clinical evaluation and end-organ injury assessment is recommended. 2