• Emily L Ho, Lauren C Tantalo, Trudy Jones, Sharon K Sahi, and Christina M Marra.
• From the Department of Neurology, University of Washington, Seattle, WA.
• Sex Transm Dis. 2015 Jan 1; 42 (1): 48-52.

BackgroundThe laboratory diagnosis of neurosyphilis rests upon identifying cerebrospinal fluid (CSF) abnormalities, including CSF-Venereal Disease Research Laboratory (VDRL) reactivity. The CSF-VDRL may not be available in the parts of the world where neurosyphilis is most common. Treponemal immunochromatographic strip tests (ICSTs) have been developed as point-of-care tests on blood for syphilis diagnosis in resource-limited settings.MethodsWe optimized 3 commercial ICSTs for performance on CSF and tested CSF samples from 217 patients with syphilis. The Syphicheck-WB test (Qualpro Diagnostics, Goa, India; "Syphicheck") was chosen for further study based on agreement with CSF-VDRL test results. We determined CSF-Syphicheck titers for 152 samples. We modified the CSF-Syphicheck for point-of-care testing in a US sexually transmitted diseases clinic and compared results on 102 paired centrifuged and uncentrifuged CSF samples obtained in the laboratory to the results obtained at point of care; results of samples diluted 1:4 were compared in a subset.ResultsThe diagnostic sensitivity of a reactive CSF-Syphicheck (62%-64%) and the diagnostic specificity of a CSF-Syphicheck titer at or above 1:4 (79%-81%) were equivalent to the CSF-VDRL (54%-69% sensitivity, 73%-75% specificity) for laboratory and clinical neurosyphilis diagnoses. The CSF-Syphicheck normalized after neurosyphilis therapy similarly to the CSF-VDRL. The modified CSF-Syphicheck performed well at the point of care, albeit with better performance on cell-free compared with uncentrifuged CSF.ConclusionsCerebrospinal fluid treponemal ICSTs hold promise for point-of-care neurosyphilis diagnosis in regions where the CSF-VDRL is not available. Further study should address the performance of CSF ICSTs in resource-limited settings.

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