Elecsys® HIV combi PT

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

Elecsys® HIV Combi PT
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

The Elecsys® HIV combi PT is a highly sensitive and specific fourth generation electrochemiluminescence immunoassay (ECLIA) for the qualitative detection of HIV-1 p24 antigen and antibodies to HIV-1, including group O, and HIV-2 in human serum or plasma.7

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

Elecsys® HIV Combi PT

  • Systems

    cobas e 411 analyzer, cobas e 601 / cobas e 602 modules

  • Testing Time

    27 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

    COI <0.9 = non-reactive
    0.9 ≤COI <1.0 = gray zone
    COI ≥1 = reactive

  • 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 as well as L-heparin and EDTA plasma tubes containing separating gel

  • Sample volume

    40 μL

  • Onboard stability

    28 days

  • Intermediate precision in positive samples

    cobas e 411 analyzer: CV 2.1– 3.7 %
    cobas e 601 / cobas e 602 modules CV 2.2 – 3.6 %


  • Clinical sensitivity

    100 % (total n = 1,532; HIV-1 group M subtypes A-J and group O patient samples n = 975;
    HIV-2 patient samples n = 472; patient samples positive for HIV-1 Ag only n = 85)

  • Clinical specificity

    99.88 % (n = 7,343 blood donors)
    99.81 % (n = 4,103 diagnostic routine samples including pregnant women and dialysis patients)

  • Analytical sensitivity

    ≤2 IU/mL, WHO International Standard HIV-1-p24 Antigen, NIBSC code 90/636


  1. Maartens G, Celum C, Lewin SR. HIV infection: epidemiology, ptahogenesis, 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;17:1871-9.
  5. Busch 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 uman immunodeficiency virus antibody screening assay. Journal of Virological Methods. 198;75:27-38.
  7. Elecsys® HIV combi PT Pack Inserts for 08924163190, 08924180190, 2022-09, V1.0.