TABLE 1.

VRE testing results^a

Incubation duration (h) and test category	Species	No. of isolates with indicated result
		TP	TN	FP	FN	n	% Sensitivity	% Specificity	PPV (%)	NPV (%)
24
CVRE alone	VREfm	107	273	3	17	400	86.3	98.9	97.3	94.1
	VREfs	16	379	3	2	400	88.9	99.2	84.2	99.5
	VREfm and VREfss	123	652	6	19	800	86.6	99.1	95.3	97.2
CVRE + catalase,	VREfm	107	274	2	17	400	86.3	99.3	98.2	94.2
Gram stain	VREfs	16	379	3	2	400	88.9	99.2	84.2	99.5
	VREfm and VREfs	123	653	5	19	800	86.6	99.2	96.1	97.2
48
CVRE alone	VREfm	123	272	4	1	400	99.2	98.6	96.9	99.6
	VREfs	17	373	10	0	400	100.0	97.4	63.0	100.0
	VREfm and VREfs	140	651	7	2	800	98.6	98.9	95.2	99.7
CVRE + catalase,	VREfm	123	274	2	1	400	99.2	99.3	98.4	99.6
Gram stain	VREfs	17	378	5	0	400	100.0	98.7	77.3	100.0
	VREfm and VREfs	140	652	6	2	800	98.6	99.1	95.9	99.7

^aTP (true positive), mauve or green colonies on CVRE, black on BEAV, confirmed by Vitek and MIC testing to represent VRE; TN (true negative), no mauve or green colonies on CVRE, no VRE from BEAV; FP (false positive), mauve or green colonies on CVRE, no VRE isolated on BEAV; FN (false negative), no mauve or green colonies on CVRE, VRE isolated on BEAV. “CVRE alone” data do not include catalase and Gram stain results. “CVRE + catalase + Gram stain” data include CVRE results along with catalase and Gram stain results.