Could the new HIV combined p24 antigen and antibody assays replace p24 antigen specific assays?

J Virol Methods. 2007 Jul;143(1):86-94. doi: 10.1016/j.jviromet.2007.02.013. Epub 2007 Mar 28.


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.

Publication types

  • Evaluation Study

MeSH terms

  • AIDS Serodiagnosis / methods*
  • Acquired Immunodeficiency Syndrome / diagnosis*
  • Acquired Immunodeficiency Syndrome / immunology
  • HIV
  • HIV Antibodies / blood*
  • HIV Core Protein p24 / analysis*
  • HIV Core Protein p24 / immunology
  • Immunologic Tests
  • Reagent Kits, Diagnostic
  • Sensitivity and Specificity


  • HIV Antibodies
  • HIV Core Protein p24
  • Reagent Kits, Diagnostic