title: Failure to confirm HIV infection in two end-stage HIV/AIDS patients using a popular commercial line immunoassay.
abstract: Immunoassays using either viral lysate (Western blot) or recombinant/synthetic antigen (immunoblot) for anti-HIV capture are still the preferred method to confirm HIV infection. Two cases of HIV-1-infected patients presented with acquired immunodeficiency syndrome (AIDS)-defining illnesses. Laboratory tests were performed using multiple commercial HIV test kits on multiple sera from both patients over several weeks. Both patients were strongly positive on the anti-HIV/p24 antigen combined screening assay. Yet, HIV-1 infection could not be confirmed using a popular commercial immunoassay. Eventually, HIV infection was confirmed using an alternative commercial Western blot assay as well as an HIV quantitative PCR test. In laboratories without nucleic acid testing (NAT) for HIV, indeterminate results may delay confirmation of HIV infection, if commercial line immunoassays alone are available. Some end-stage HIV/AIDS patients may not produce antibodies to specific HIV antigens and may therefore give indeterminant or negative results on some immunoassays, depending on the type of antigen used. This report highlights the utility of having NAT available when diagnosing difficult cases of HIV infection, especially in light of the recent Centers for Disease Control and Prevention move towards more universal, routine, HIV testing.
authors.affiliation: Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR. julian.tang@cuhk.edu.hk
authors.forename: Julian W
authors.initials: JW
authors.lastname: Tang
authors.forename: Bonnie C K
authors.initials: BC
authors.lastname: Wong
authors.forename: Edman
authors.initials: E
authors.lastname: Lam
authors.forename: Vivien
authors.initials: V
authors.lastname: Tai
authors.forename: Nelson
authors.initials: N
authors.lastname: Lee
authors.forename: Clive S
authors.initials: CS
authors.lastname: Cockram
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Chan
mesh_terms: D000328:Adult; D015153:Blotting, Western; D005188:False Negative Reactions; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000175:diagnosis* / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008297:Male; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000097:blood
chemical_list: D015483:HIV Antibodies; D012367:RNA, Viral