Table 3.

Diagnostic characteristics of systemic inflammatory response syndrome (SIRS) criteria^a,^b for critical illness in admitted emergency department (ED) patients; n = 1152.^c

	Sn (%)	95% CI (%)	Sp (%)	95% CI (%)	LR+	95% CI	LR−	95% CI
All patients (n = 1152)
≥1 SIRS criteria	85	80, 89	29	26, 32	1.2	1.1, 1.3	0.5	0.4, 0.7
≥ 2 SIRS criteriad	52	46, 58	65	62, 68	1.5	1.3, 1.7	0.7	0.6, 0.8
≥3 SIRS criteria	22	17, 27	89	87, 91	2.0	1.5, 2.7	0.9	0.8, 0.9
4 SIRS criteria	5	3, 9	98	96, 99	2.2	1.1, 4.3	1.0	0.9, 1.0
Patients with presumed infection (n = 313)e
≥1 SIRS criteria	90	83, 95	19	14, 25	1.1	1.0, 1.2	0.5	0.3, 1.0
≥2 SIRS criteriad	66	56, 75	52	45, 59	1.4	1.1, 1.7	0.6	0.5, 0.9
≥3 SIRS criteria	27	19, 37	77	71, 83	1.2	0.8, 1.8	0.9	0.8, 1.1
4 SIRS criteria	7	3, 14	94	90, 97	1.2	0.5, 2.9	1.0	0.9, 1.1
Patients without presumed infection (n = 839)e
≥1 SIRS criteria	81	74, 87	32	29, 36	1.2	1.1, 1.3	0.6	0.4, 0.8
≥2 SIRS criteriad	43	36, 51	69	66, 73	1.4	1.2, 1.7	0.8	0.7, 0.9
≥3 SIRS criteria	18	13, 25	93	91, 95	2.5	1.7, 3.8	0.9	0.8, 1.0
4 SIRS criteria	4	2, 9	99	98, 99	3.2	1.2, 8.5	1.0	0.9, 1.0

Abbreviations: SIRS, systemic inflammatory response syndrome; ED, emergency department; Sn, sensitivity; Sp, specificity; CI, confidence interval; LR, likelihood ratio.

^aSIRS was defined as 2 or more of the following: temperature >38° C or <36° C; heart rate >90 per minute; respiratory rate >20 per minute; or white blood cell count (WBC) >12,000 or <4,000/μL.

^b53 patients were missing 1 of the 4 SIRS criteria variables. All instances of missing criteria variables were assumed to not have met that specific SIRS criterion.

^cCritical illness defined as ≥24 hours in the intensive care unit or in hospital death.

^dThe results are bolded for the original SIRS criteria cutoff defined as 2 or more SIRS criteria.

^ePresumed infection defined as having received antibiotics within 48 hours of admission.