title: Use of cerebrospinal fluid enzyme immunoassay for diagnosis of neurosyphilis.
abstract: Neurosyphilis is a difficult clinical stage of syphilis as there is no ideal method for diagnosis and workup requires lumbar puncture which may sometimes provide ambiguous results especially in HIV co-infected patients. Enzyme immunoassay is a widely used screening test for syphilis in serum, but its test performance was not well studied in cerebrospinal fluid. To examine the diagnostic performance of cerebrospinal fluid-enzyme immunoassay (CSF-EIA) in neurosyphilis, we conducted a prospective study for two years. All consecutive patients admitted for workup of neurosyphilis under the Social Hygiene Service, in Hong Kong, were included. Laboratory tests on CSF included several serological tests, CSF cell count, and protein. Forty-five patients were prospectively recruited, of which 29 people were living with HIV / AIDS. Using diagnostic case definition standard stipulated in the IUSTI 2008 guidelines, 17 patients satisfied the diagnosis of neurosyphilis. The CSF-EIA test provided 100% in both sensitivity and negative predictive value; its specificity was 46.4% (13/28, 95% CI 31.8-61%). Specificity improved to 80.8% (95% CI: 68.4-93.2%) with optical density cut-off value at 1.4 for cases with CSF red cell counts <600/mm(3) This is the first study on use of CSF-EIA in neurosyphilis. CSF-EIA showed high sensitivity and high negative predictive value in the study population and the presence of CSF red cells < 600/mm(3)might not affect its accuracy.
authors: Social Hygiene Service, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, Hong Kong cydavis@gmail.com.
authors: Yung
authors: Y
authors: Chan
authors: Social Hygiene Service, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, Hong Kong.
authors: Kwok-Hung
authors: KH
authors: Yeung
authors: Social Hygiene Service, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, Hong Kong.
authors: Hing-Fung
authors: HF
authors: Ho
authors: Social Hygiene Service, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, Hong Kong.
authors: King-Man
authors: KM
authors: Ho
authors: Public Health Laboratory Centre, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, Hong Kong.
authors: Edman
authors: E
authors: Tin-Keung Lam
authors: Public Health Laboratory Centre, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, Hong Kong.
authors: Wai-Lin
authors: WL
authors: Leung
authors: Stanley Ho Centre for Emerging Infectious Diseases, School of Public Health and Primary care, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong.
authors: Kai-Man
authors: KM
authors: Kam
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000134:cerebrospinal fluid*; D005260:Female; D006723:Hong Kong; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009494:Neurosyphilis / Q000134:cerebrospinal fluid* / Q000175:diagnosis*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013588:Syphilis Serodiagnosis; D014210:Treponema pallidum / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial
keywords: Syphilis; Treponema pallidum; cerebrospinal fluid; diagnosis; enzyme immunoassay; neurosyphilis; sexually transmitted infection