Table 3.

Sensitivity, specificity and predictive value of proposed risk assessment criteria

Screening criteria	Frequencies	Sensitivity	Specificity	PPV	NPV	ROC
All assessment categories combined	TP:43 FP:16 FN:26 TN:655	62.3%	97.6%	72.9%	96.2%	0.780
Two major risk factors	TP:23 FP:7 FN:46 TN:664	33.3%	98.9%	76.7%	93.5%	0.662
One major and two minor risk factors	TP:20 FP:6 FN:49 TN:665	29.0%	99.1%	76.9%	93.1%	0.641
Three minor risk factors	TP:12 FP:4 FN:57 TN:667	17.4%	99.4%	75.0%	92.1%	0.584

TP = True positives. FP = False positives. TN = True negatives. FN = False negatives

PPV = Positive predictive value. NPV = Negative predictive value