Table 2. Performance of some chest pain characteristics in predicting acute coronary syndrome (ACS).

Clinical feature	Sensitivity (%)	Specificity (%)	LR+ (95% CI)	LR− (95% CI)	PPV	NPV
Pain irradiation to both arms	11	96	2.6 (1.8–3.7)	0.93 (0.89–0.96)	28	12
Pain similar to prior ischemia	47	79	2.2 (2.0–2.6)	0.67 (0.60–0.74)	25	9
Change in pain pattern over the prior 24 hours	27	86	2.0 (1.6–2.4)	0.84 (0.79–0.90)	23	11
Typical chest pain	66	66	1.9 (0.94–2.9)	0.52 (0.35–0.69)	22	7
Systolic blood pressure <100 mmHg	3.1	99	3.9 (0.98–15)	0.98 (0.95–1)	37	13
Lung rales	9	95	2.0 (1.0–4.0)	0.95 (0.89–1.0)	23	12

LR+, positive likelihood ratio; LR−, negative likelihood ratio; PPV, positive predictive value; NPV, negative predictive value. Modified from (32).