Elecsys® HIV combi PT

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 three 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

Elecsys® HIV combi PT is an immunoassay for the in vitro qualitative determination of HIV‑1 p24 antigen and antibodies to HIV‑1 (HIV‑1 groups M and O) and HIV‑2 in human serum and plasma. Elecsys® HIV combi PT is intended to be used as an aid in the diagnosis of HIV‑1 and/or HIV‑2 infection, including acute or primary HIV‑1 infection. The assay may also be used as an aid in the diagnosis of HIV‑1/HIV‑2 infection in subjects greater than 2 years of age and in pregnant women. The Elecsys® HIV combi PT assay is not intended for the screening of blood or plasma donors.7



  1. Maartens, G., Celum, C., Lewin, S.R. (2014). HIV infection: epidemiology, pathogenesis, treatment, and prevention. Lancet 384, 258-71.
  2. Killian, M.S., Levy, J.A. (2011). HIV/AIDS: 30 years of progress and future challenges. Eur J Immunol 41, 3401-11.
  3. Shaw, G.M., Hunter, E. (2012). HIV transmission. Cold Spring Harb Perspect Med. 2:a006965.
  4. Fiebig, E.W., Wright, D.J., Rawal, B.D. et al. (2003). Dynamics of HIV viremia and antibody seroconversion in plasma donors: implications for diagnosis and staging of primary HIV infection. AIDS 17, 1871-9.
  5. Busch, M.P., Lee, L.L., Satten, G.A. et al. (1995). Time course of detection of viral and serologic markers preceding human immunodeficiency virus type 1 seroconversion: implications for screening of blood and tissue donors. Transfusion 35, 91-7.
  6. Guertler, L., Muehlbacher, A., Michl, U. et al. (1998). Reduction of the diagnostic window with a new combined p24 antigen and human immunodeficiency virus antibody screening assay. Journal of Virological Methods 75, 27-38.
  7. HIV combi PT Pack Insert 2017-10, V1.0.

Elecsys® HIV Combi PT

  • System

    cobas e 602 module

  • 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

    <1.0 = non-reactive
    ≥1.0 = reactive

  • 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 

  • Sample volume

    39 μL

  • Onboard stability

    28 days

  • Intermediate precision in positive samples

    cobas e 602 module CV 0.39 – 8.90%

  • Clinical sensitivity

    100% (total n = 1,460; HIV-1 positive 
    100% HIV-2 Ab positive

  • Clinical specificity

    99.94% (n = 6,843 low risk population)

  • Analytical sensitivity

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