Table 2.

Comparison of pretest probability estimates for acute coronary syndrome using two techniques in a validation population.

	Category of Pretest Probability
	Very Low (<2%)	Low (2 to <10%)	Moderate (10 to 30%)	High (>30%)	Indeterminate*
Attribute Matching
Number with ACS†	28	189	250	9	125
Total in category‡	1670	2953	1453	28	955
Prevalence of ACS	1.7%	6.4%	17.2%	32.1%	13.1%
% of all patients assessed	23.7%	41.8%	20.6%	0.4%	13.5%
Logistic Regression
Number with ACS†	4	59	272	266	NA
Total in category‡	244	1356	3813	1646	NA
Prevalence of ACS	1.6%	4.4%	7.1%	16.2%	NA
% of all patients assessed	3.5%	19.2%	54.0%	23.3%	NA

*Estimates from attribute matching with match size <50. Does not apply to logistic regression.

†Total number of patients with ACS = 601

‡Total number patients in validation study = 7059

Abbreviations: ACS acute coronary syndrome.