title: Cerebrospinal Fluid Treponema pallidum Particle Agglutination Assay for Neurosyphilis Diagnosis.
abstract: Limited data suggest that the cerebrospinal fluidTreponema pallidumparticle agglutination assay (CSF-TPPA) is sensitive and a CSFTreponema pallidumhemagglutination assay (CSF-TPHA) titer of ≥1:640 is specific for neurosyphilis diagnosis. CSF-TPPA reactivity and titer were determined for a convenience sample of 191 CSF samples from individuals enrolled in a study of CSF abnormalities in syphilis (training data set). The sensitivity of a reactive test and the specificity for reactivity at serial higher CSF dilutions were determined. Subsequently, CSF-TPPA reactivity at a 1:640 dilution was determined for all available samples from study participants enrolled after the last training sample was collected (validation data set,n= 380). Neurosyphilis was defined as (i) a reactive CSF Venereal Disease Research Laboratory test (CSF-VDRL), (ii) detection ofT. pallidumin CSF by reverse transcriptase PCR, or (iii) new vision loss or hearing loss. In the training data set, the diagnostic sensitivities of a reactive CSF fluorescent treponemal antibody absorption test (CSF-FTA-ABS) and a reactive CSF-TPPA did not differ significantly (67 to 98% versus 76 to 95%). The specificity of a CSF-TPPA titer of ≥1:640 was significantly higher than that of lower dilutions and was not significantly different from that of CSF-VDRL. In the validation data set, the diagnostic specificity of a CSF-TPPA titer of ≥1:640 was high and did not differ significantly from that of CSF-VDRL (93 to 94% versus 90 to 91%). Ten CSF samples with a nonreactive CSF-VDRL had a CSF-TPPA titer of ≥1:640. If a CSF-TPPA titer of ≥1:640 was used in addition to a reactive CSF-VDRL, the number of neurosyphilis diagnoses would have increased from 47 to 57 (21.3%). A CSF-TPPA titer cutoff of ≥1:640 may be useful in identifying patients with neurosyphilis when CSF-VDRL is nonreactive.
authors.affiliation: Department of Neurology, Harborview Medical Center, University of Washington, Seattle, Washington, USA cmarra@u.washington.edu.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Marra
authors.affiliation: Department of Neurology, Harborview Medical Center, University of Washington, Seattle, Washington, USA.
authors.forename: Clare L
authors.initials: CL
authors.lastname: Maxwell
authors.affiliation: Department of Medicine, Harborview Medical Center, University of Washington, Seattle, Washington, USA.
authors.forename: Shelia B
authors.initials: SB
authors.lastname: Dunaway
authors.affiliation: Department of Neurology, Harborview Medical Center, University of Washington, Seattle, Washington, USA.
authors.forename: Sharon K
authors.initials: SK
authors.lastname: Sahi
authors.affiliation: Department of Neurology, Harborview Medical Center, University of Washington, Seattle, Washington, USA.
authors.forename: Lauren C
authors.initials: LC
authors.lastname: Tantalo
mesh_terms: D000328:Adult; D000372:Agglutination Tests / Q000379:methods*; D002555:Cerebrospinal Fluid / Q000382:microbiology*; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009494:Neurosyphilis / Q000175:diagnosis*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014210:Treponema pallidum / Q000276:immunology*
keywords: TPPA; diagnosis; human immunodeficiency virus; neurosyphilis; syphilis