title: Could the new HIV combined p24 antigen and antibody assays replace p24 antigen specific assays?
abstract: The performance of twelve HIV combined p24 antigen and antibody assays available in Europe were compared. The assays were examined with a total of 1983 samples that included 1005 unselected HIV negative samples, 7 HIV-1 p24 Ag reference samples with HIV-1 Ag, 10 samples of a HIV antigen sensitivity commercial panel, 124 samples of 31 p24 antigen panels of different HIV-1 subtypes, 168 members of 24 HIV-1 seroconversion panels, 559 HIV-1 (groups M and O) antibody positive samples and 110 HIV-2 antibody positive samples. The specificity ranged from 99.4 to 100%. Ten of the 12 assays detected all anti-HIV positive samples irrespective of genotype while two assays missed one sample each (one subtype F and one subtype C). The combined assays could be classified into three groups. The first includes two assays (Enzygnost HIV Integral and Vironostika Ag/Ab) that have a clinical sensitivity similar to the two antibody only assays. The second includes the seven assays that detected infection after the p24 antigen only assay and show a delay from 3.3 to 5.17 days after HIV-1 RNA. The third group detected the infection before the p24 antigen assay and less than 3 days after nucleic acid testing (NAT). The improved ability to detect p24 Ag, at levels similar to specific HIV Ag assays, suggests that these new HIV combined Ag/Ab assays could replace p24 antigen only assays in situations for blood or organ screening when NAT is not feasible or not affordable.
authors: Laboratoire L.C.L. (Claude Lévy), Ivry sur Seine, Paris, France. t.ly@lablcl.com
authors: Thoai Duong
authors: TD
authors: Ly
authors: Anne
authors: A
authors: Ebel
authors: Véronique
authors: V
authors: Faucher
authors: Valentine
authors: V
authors: Fihman
authors: Syria
authors: S
authors: Laperche
mesh_terms: D015492:AIDS Serodiagnosis / Q000379:methods*; D000163:Acquired Immunodeficiency Syndrome / Q000175:diagnosis* / Q000276:immunology; D006678:HIV; D015483:HIV Antibodies / Q000097:blood*; D016655:HIV Core Protein p24 / Q000032:analysis* / Q000276:immunology; D007159:Immunologic Tests; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
chemical_list: D015483:HIV Antibodies; D016655:HIV Core Protein p24; D011933:Reagent Kits, Diagnostic