title: Evaluation of HIV antibody and antigen/antibody combination ELISAs for use in an alternative confirmatory HIV testing strategy in Dar es Salaam, Tanzania.
abstract: The aim of this study was to evaluate the performance of two antibody enzyme-linked immunosorbent assays (ELISAs) [Vironostika Uni-Form II plus O and Enzygnost anti-HIV-1/2 Plus], and two antigen/antibody combination ELISAs [Murex and Vironostika HIV Uni-Form II] for use in an alternative confirmatory HIV diagnostic testing strategy in Dar es Salaam, Tanzania. Altogether, 1380 serum samples were included. All ELISA reactive samples were tested using the Inno-Lia antibody assay and discrepant samples were tested on the Innotest p24 antigen assay. Three hundred and one (21.8%) samples were confirmed HIV-1 antibody positive by Inno-Lia including 27/508 (5.3%) from blood donors, 65/511 (12.7%) from pregnant women and 209/361 (57.9%) from hospital patients. The sensitivity at initial testing was 100% (95% CI; 98.8-100%) for all assays except Vironostika Uni-Form II plus O (99.7%; 95% CI; 98.2-99.9%) which showed one false negative sample at initial testing but 100% sensitivity after repeat testing. The final specificity at repeat testing was 100% (95% CI; 99.7-100%) for Enzygnost anti-HIV-1/2 Plus, 99.4% (95% CI; 98.8-99.8%) for each of the antigen/antibody combination ELISAs and 97.9% (95% CI; 96.8-98.6%) for Vironostika plus O ELISA. An alternative confirmatory HIV testing strategy based on initial testing on any of the two antigen/antibody assays followed by testing of reactive samples on the Enzygnost anti-HIV-1/2 Plus assay gave 100% specificity (95% CI; 99.7-100%).
authors.affiliation: Department of Microbiology and Immunology, Muhimbili University College of Health Sciences, P.O. Box 65001, Dar es Salaam, Tanzania.
authors.forename: Said
authors.initials: S
authors.lastname: Aboud
authors.forename: Willy
authors.initials: W
authors.lastname: Urassa
authors.forename: Eligius
authors.initials: E
authors.lastname: Lyamuya
authors.forename: Fred
authors.initials: F
authors.lastname: Mhalu
authors.forename: Gunnel
authors.initials: G
authors.lastname: Biberfeld
mesh_terms: D015492:AIDS Serodiagnosis / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015483:HIV Antibodies / Q000097:blood*; D016655:HIV Core Protein p24 / Q000097:blood*; D015497:HIV-1 / Q000276:immunology; D015498:HIV-2 / Q000276:immunology; D006801:Humans; D012680:Sensitivity and Specificity
chemical_list: D015483:HIV Antibodies; D016655:HIV Core Protein p24