Table 1.

Clinical validation of questionnaire appraising risk of coronary heart disease. Values are numbers of patients

	Risk of heart disease by clinical assessment
		High	Low	Total
Risk of heart disease by questionnaire
High		35	5	40
Low		5	55	60
Total		40	60	100

Sensitivity = 87.5% (95% confidence interval 73.2% to 95.8%)  

Specificity = 91.7% (81.6% to 97.2%)  

Positive predictive value = 87.5% (73.2% to 95.8%)  

Negative predictive value = 91.7% (81.6% to 97.2%)  

Proportion inappropriately labelled = 10% (4.9% to 17.6%).