Table 5.

Performance characteristics of PCR, FTA-ABS, TPPA, and INNO-LIA assays for the diagnosis of symptomatic and asymptomatic neurosyphilis in HIV-infected patients with early syphilis^a

Assay	Clinical statusb	No. of patients	No. of NS casesc	Performance characteristics (%)				Likelihood ratios
				Sensitivity	Specificity	PPV	NPV	Positive	Negative
PCR	S	50	18	61	81	65	79	3.26	0.48
	A	58	6	50	58	12	91	1.18	0.87
FTA-ABS	S	49	18	100	13	40	100	1.15	0
	A	51	5	100	11	11	100	1.12	0
TPPAd	S	49	18	72	52	46	76	1.49	0.54
	A	51	4	50	47	7	92	0.94	1.07
INNO-LIAd	S	39	15	100	13	42	100	1.14	0
	A	44	5	100	13	13	100	1.15	0

^aFTA-ABS, fluorescent treponemal antibody absorption; TPPA, Treponema pallidum particle agglutination.

^bS, presence of neurological symptoms; A, absence of neurological symptoms.

^cNS, neurosyphilis.

^dPatients with indeterminate results were excluded (TPPA, n = 3; INNO-LIA, n = 10).