Table 3.

Predictive Value of PTSD Diagnosis by the Number of Trauma Screening Items Endorsed (n = 88).

		Dx Pos.	Dx Neg.	Sensitivity (95% CI)	Specificity (95% CI)	Pred. Value Pos. (95% CI)	Pred. Value Neg. (95% CI)	C-Statistic1	Fisher's Exact P-value
4 PTSD Items Endorsed	Pos.	45	14	78% (67% – 88%)	53% (35% – 71%)	76% (65% – 87%)	55% (37% – 73%)	0.66	.0046
	Neg.	13	16
5 PTSD Items Endorsed	Pos.	39	10	67% (55% – 79%)	67% (50% – 84%)	80% (68% – 91%)	51% (36% – 67%)	0.67	.0033
	Neg.	19	20
6 PTSD Items Endorsed	Pos.	28	3	48% (35% – 61%)	90% (79% – 100%)	90% (80% – 100%)	47% (34% – 60%)	0.69	<.001
	Neg.	30	27

Note: ¹The c-statistic is the area under the Receiver Operating Characteristic (ROC) curve, which measures test performance.