Table 2. AUC, sensitivity, specificity, PPV and NPV of IgA-gH/gL, IgA-VCA, EBV DNA and their combinations for detection of NPC in the training cohort.

Test	AUC (95%)	pa	Sensitivity		pb	Specificity		pb	PPV		pc	NPV		pc
			%	95% CI		%	95% CI		%	95% CI		%	95% CI
gH/gL	0.893 (0.862-0.924)		83.7	78.7-88.7		82.3	77.0-87.6		83.3	78.2-88.4		82.7	77.4-88.0
VCA	0.933 (0.906-0.959)		84.6	79.7-89.5		93.4	89.9-96.9		93.1	89.5-96.7		85.3	80.6-90.0
EBV DNA	0.849 (0.810-0.889)		71.6	65.5-77.7		94.9	91.8-98.0		93.7	89.9-97.5		76.1	70.8-81.4
gH/gL vs. VCA		NS			NS			0.002			0.003			NS
gH/gL vs. EBVDNA		0.046			0.004			<0.001			0.002			NS
VCA vs. EBVDNA		<0.001			0.001			NS			NS			0.013
gH/gL + VCA	0.980 (0.970-0.991)		88.5	84.2-92.8		97.0	94.6-99.4		96.8	94.3-99.3		88.9	84.7-93.1
gH/gL + EBV DNA	0.941 (0.919-0.963)		87.5	83.0-92.0		89.4	85.1-93.7		89.7	83.5-93.9		87.2	82.6-91.8
VCA + EBV DNA	0.967 (0.949-0.985)		87.5	83.0-92.0		97.4	95.2-99.6		97.3	95.0-99.6		88.1	83.8-92.4
gH/gL vs.gH/gL + VCA		<0.001			NS			<0.001			<0.001			NS
VCA vs.gH/gL + VCA		<0.001			0.039			NS			NS			NS
EBV DNA vs.gH/gL + VCA		<0.001			<0.001			NS			NS			<0.001
gH/gL + VCA vs. gH/gL + EBV DNA		<0.001			NS			0.001			0.005			NS
gH/gL + VCA vs. VCA + EBV DNA		NS			NS			NS			NS			NS

PPV, positive predictive value; NPV, negative predictive value; NS, not significant; gH/gL, enzyme-linked immunosorbent assay detection of IgA antibodies against EBV glycoprotein complex gH/gL; VCA, immunofluorescence assay for IgA antibodies against viral capsid antigen; EBV DNA, qPCR test for plasma circulating EBV DNA.

^aZ test.

^bMcNemar's paired-sample test.

^cChi-squared test.