title: Evaluation of a modified commercial assay in detecting antibody to hepatitis C virus in oral fluids and dried blood spots.
abstract: Oral fluid testing is an effective alternative to serum antibody testing for surveillance of human immunodeficiency virus (HIV) and hepatitis B infections, and is being extended to hepatitis C infections. The objective of this study was to determine and compare the sensitivity and specificity of a modified commercial assay for the detection of antibody to hepatitis C virus (anti-HCV) in oral fluids collected by two different oral fluid collection devices (the Epitope OraSure trade mark and Sarstedt Salivette ) and in dried fingerprick blood spots. In this study, 253 anti-HCV seropositive patients and 394 blood donors (all anti-HCV negative) were recruited between August 2000 and January 2001. Each participant provided oral fluid specimens by OraSure and Salivette, and at least one dried blood spot. Serum specimens were collected from the patients whenever possible. For those injecting drug users who did not provide a serum specimen, HCV status was established on the basis of previous testing. All the nonserum samples were tested for the presence of anti-HCV, using a modified Ortho HCV 3.0 SAVe enzyme-linked immunosorbent assay (ELISA) protocol. The recommended preliminary cutoffs for the modified ELISA were suboptimal. Further, the sensitivity, specificity, and positive and negative predictive values could be improved by varying the cutoff and taking into account the likely prevalence of HCV in the population under investigation. For instance, given a population with a 50% prevalence of anti-HCV, the optimal sensitivities of the modified assay on OraSure, Salivette, and dried blood spots were 92%, 83%, and virtually 100%, respectively, in contrast to 83%, 59%, and 99% using the preliminary cutoffs. The respective optimal specificities were 99%, 93%, and 100%. In conclusion, oral fluids collected by the OraSure device provide an extremely useful method to conduct public health surveillance of not only HIV, but also hepatitis C, among injecting drug users. In addition, dried blood spot specimens may be useful for surveillance and could be employed as a first line diagnostic specimen.
authors.affiliation: Centre for Research on Drugs and Health Behaviour, Department of Social Science and Medicine, Faculty of Medicine, Imperial College London, United Kingdom. a.judd@imperial.ac.uk
authors.forename: Ali
authors.initials: A
authors.lastname: Judd
authors.forename: John
authors.initials: J
authors.lastname: Parry
authors.forename: Matthew
authors.initials: M
authors.lastname: Hickman
authors.forename: Tamara
authors.initials: T
authors.lastname: McDonald
authors.forename: Laura
authors.initials: L
authors.lastname: Jordan
authors.forename: Kim
authors.initials: K
authors.lastname: Lewis
authors.forename: Marcela
authors.initials: M
authors.lastname: Contreras
authors.forename: Geoff
authors.initials: G
authors.lastname: Dusheiko
authors.forename: Graham
authors.initials: G
authors.lastname: Foster
authors.forename: Noël
authors.initials: N
authors.lastname: Gill
authors.forename: Katie
authors.initials: K
authors.lastname: Kemp
authors.forename: Janice
authors.initials: J
authors.lastname: Main
authors.forename: Iain
authors.initials: I
authors.lastname: Murray-Lyon
authors.forename: Mark
authors.initials: M
authors.lastname: Nelson
mesh_terms: D001800:Blood Specimen Collection / Q000379:methods*; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000276:immunology / Q000821:virology*; D018937:Hepatitis C Antibodies / Q000032:analysis* / Q000097:blood*; D006801:Humans; D011933:Reagent Kits, Diagnostic; D012463:Saliva / Q000276:immunology / Q000821:virology*; D012680:Sensitivity and Specificity
chemical_list: D018937:Hepatitis C Antibodies; D011933:Reagent Kits, Diagnostic