Elecsys® HIV Duo

Immunoassay for the qualitative determination of HIV p24 antigen and antibodies to HIV

Elecsys HIV Duo
Immunoassay for the qualitative determination of HIV p24 antigen and antibodies to HIV

The human immunodeficiency virus (HIV) is the causative agent of acquired immunodeficiency syndrome (AIDS) and has been a major global burden for over four decades.1,2 HIV is transmitted through sexual contact, contaminated blood and blood products or from an HIV-infected mother to her child before, during and after birth.3 Diagnosis of an HIV infection can be made as early as 2 - 3 weeks after infection, based on the detection of HIV p24 antigen in the blood.4,5 Anti-HIV antibodies are detectable in serum from around 4 weeks post-infection.4,6

With the Elecsys® HIV Duo assay, HIV-1 p24 antigen (HIV Ag), as well as antibodies to HIV-1 and HIV-2 (anti-HIV) can be detected in parallel with two separate determinations. On the basis of these determinations, the Elecsys® HIV Duo main result is calculated automatically by the analyzer. The subresults for HIV Ag and anti-HIV can be used as an aid in the selection of the confirmation algorithm for reactive samples.7

Elecsys® HIV Duo

Elecsys® HIV Duo

  • Systems

    cobas e 402 / cobas e 801 analytical units

  • Testing Time

    18 minutes

  • Test principle

    Double antibody or antigen sandwich immunoassay for the detection of HIV antigen and anti-HIV antibodies, respectively.


  • Calibration

    Individual 2-point calibration for HIV antigen and anti-HIV antibodies

  • Interpretation

    HIV Ag: COI <1.0 = non-reactive for HIV-1 Ag
    HIV Ag: COI ≥1.0 = reactive in the HIV Ag module

    Anti-HIV:  COI <1.0 = non-reactive for anti-HIV antibodies 
    Anti-HIV: COI ≥1.0 = reactive in the anti-HIV module

    HIV Duo main result This result is calculated automatically based on the HIV Ag and anti-HIV COI:

    HIV DUO: COI <1.0 = non-reactive
    HIV DUO: COI ≥1.0 = reactive

  • cobas e flow

    Duplicate repeat of initially reactive samples

  • Traceability

    The HIV antigen detection method has been standardized against the WHO International Standard HIV 1 p24 Antigen (NIBSC code 90/636). No internationally accepted standard for anti-HIV-1 and anti-HIV-2 exists.

  • Sample material

    Serum collected using standard sampling tubes or tubes containing separating gel. Li-heparin, Na-heparin, K2-EDTA, K3-EDTA, ACD, CPD, CP2D, CPDA and Na- citrate plasma. Plasma tubes containing separating gel can be used.

    Specimen collected from living patients, blood donors, or individual organ, tissue or cell donors may be used, including donor samples obtained while the donor's heart is still beating, and cadaveric blood specimens (specimens collected post-mortem, non-heart-beating).






  • Sample volume

    60 μL 2 x 30 μL

  • Onboard stability

    16 weeks

  • Intermediate precision in positive samples

    HIV Ag: CV 2.2 – 2.8 %
    Anti-HIV: CV 2.7 – 3.6 %




  • Clinical sensitivity

    100 % (total n = 1,699; HIV-1 group M subtypes A-K, CRFs and group O patient samples n = 1,447; HIV-2 patient samples n = 202; patient samples positive for HIV-1 Ag only n = 50)

  • Clinical specificity

    99.87 % (n = 13,330 blood donors)
    99.92 % (n = 2,368 diagnostic routine samples including pregnant women and dialysis patients)

  • Analytical sensitivity

    ≤1 IU/mL, WHO International Standard HIV-1-p24 Antigen, NIBSC code 90/636


  1. Maartens G, Celum C, Lewin SR. HIV infection: epidemiology, pathogenesis, treatment, and prevention. Lancet. 2014;384:258-71.
  2. Killian MS, Levy JA. HIV/AIDS: 30 years of progress and future challenges. Eur J Immunol. 2011;41:3401-11.
  3. Shaw GM, Hunter E. HIV transmission. Cold Spring Harb Perspect Med. 2012;2:a006965.
  4. Fiebig EW et al. Dynamics of HIV viremia and antibody seroconversion in plasma donors: implications for diagnosis and staging of primary HIV infection. AIDS. 2003;17:1971-9.
  5. Busch MP et al. Time course of detection of viral and serological markers preceding human immunodeficiency virus type 1 seroconversion: implications for screening of blood and tissue donors. Transfusion. 1995;35:91-7.
  6. Guertler L et al. Reduction of the diagnostic window with a new combined p24 antigen and human immunodeficiency virus antibody screening assay. Journal of Virological Methods. 1998;75:27-38.
  7. Elecsys® HIV Duo Pack Insert 2022-08, V3.0