Table 4. AUC, sensitivity, specificity, PPV and NPV of IgA-gH/gL, IgA-VCA, EBV DNA and their combinations for detection of NPC in the validation cohort.

Test	AUC (95%)	pa	Sensitivity		pb	Specificity		pb	PPV		pc	NPV		pc
			%	95% CI		%	95% CI		%	95% CI		%	95% CI
gH/gL	0.912 (0.878-0.947)		86.9	81.3-92.5		80.3	73.8-86.8		81.0	74.7-87.3		86.3	80.4-92.2
VCA	0.950 (0.922-0.977)		81.0	74.4-87.6		95.0	91.0-98.6		94.1	89.8-98.4		83.9	78.2-89.6
EBV DNA	0.844 (0.794-0.893)		69.3	61.6-77.0		96.5	93.5-99.5		95.0	90.7-99.3		76.5	70.3-82.7
gH/gL vs. VCA		NS			NS			<0.001			0.002			NS
gH/gL vs. EBVDNA		0.009			<0.001			<0.001			0.001			NS
VCA vs. EBVDNA		<0.001			0.015			NS			NS			NS
gH/gL + VCA	0.970 (0.951-0.988)		91.2	86.5-95.9		96.5	93.5-99.5		96.2	92.9-99.5		91.9	87.5-96.3
gH/gL + EBV DNA	0.961 (0.940-0.982)		89.0	83.8-94.2		91.5	86.9-96.1		91.0	86.2-95.9		89.7	84.8-94.6
VCA + EBV DNA	0.959 (0.933-0.985)		81.0	74.4-87.6		99.3	97.9-100.0		99.0	97.2-100.0		84.4	78.9-89.9
gH/gL vs.gH/gL + VCA		<0.001			NS			<0.001			<0.001			NS
VCA vs.gH/gL + VCA		NS			0.001			NS			NS			0.03
EBV DNA vs.gH/gL + VCA		<0.001			<0.001			NS			NS			<0.001
gH/gL + VCA vs. gH/gL + EBV DNA		NS			NS			NS			NS			NS
gH/gL + VCA vs. VCA + EBV DNA		NS			0.011			NS			NS			0.04

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.