REF:

E4103 (Microwell Plate)

INTENDED USE:

This HIV Type I/Type II Antigen + Antibody ELISA Test is an enzyme-linked immunosorbent assay (ELISA) intended for qualitative detection of antigens and/or antibodies to Human Immunodeficiency Viruses (HIV) type 1(group M-O) and/or type 2 in human serum or plasma samples. The method is also known as 4th generation ELISA for HIV detection. The kit is intended for screening of blood donors and as an aid in the diagnosis of clinical conditions related to infection with HIV-1 and/or HIV-2 -the etiological agents of the acquired immunodeficiency syndrome (AIDS).

SUMMARY:

The human immunodeficiency viruses type 1 and type 2 are the etiological agents of the acquired immunodeficiency syndrome (AIDS) and related conditions. HIV has been isolated from patients with AIDS, AIDS related complex (ARC) and from healthy individuals at high risk for AIDS. Infection with HIV is followed by an acute flu-like illness. This phase may remain unnoticed and the relationship to HIV infection may not be clear in many cases. The acute phase is typically followed by an asymptomatic carrier state, which progresses to clinical AIDS in about 50% of infected individuals within 10 years after seroconversion. Serological evidence of infection with HIV may be obtained by testing for presence of HIV antigens or antibodies in serum of individuals suspected for HIV infection. Antigens can generally be detected during both acute phase and the symptomatic phase of AIDS only. The Antibodies to HIV-1 and/or HIV-2 can be detected throughout virtually the whole infection period, starting at, or shortly after the acute phase and lasting till the end stage of AIDS. Apart from sexual transmission, the principal route of infection with HIV is blood transfusion. HIV can present both in cellular and cell-free fractions of human blood. Therefore, all donations of blood or plasma should be tested due to the risk of HIV transmission through contaminated blood.

The ELISA tests for detection of HIV infection are characterized with high sensitivity, specificity and simple operation procedure. There are most appropriate for testing of large numbers of specimens and currently, internationally available are hundreds of HIV tests used in routine blood screening or clinical diagnosis. Since the first HIV ELISA tests were commercially introduced in 1985, four more generations have been developed. The 1st generation tests were based on viral lysate antigens derived from viruses that are grown in human T-lymphocyte lines. The presence of traces of host cell components in which the virions have been propagated could lead to cross-contamination and thus to very high rates of false-positive results.With the cloning of the HIV genome, improved assays based on recombinant proteins and/or synthetic peptides (known as 2nd generation), became rapidly available. The utilization of biotechnology methods allow predominantly expression of the important immunoreactive regions of the proteins and also enabled the production of combined HIV-1/HIV-2 assays. The recombinant antigen could also be produced with considerably more purity and in large amounts, and they can be bond to solid-phase surface with much tighter control over protein ratios and concentrations. The first and second generations HIV kits were based on indirect ELISA method and could detect IgG antibodies only by enzyme-labeled anti-human IgG antibody.The third generation ELISA utilized double antigen “sandwich” method: again with antigens coated on solid phase polystyrene plates, but with antibodies detection achieved with the help of another enzyme-labeled antigen. The third generation assays could detect all antibodies in sample (IgG, IgM, etc.) which significantly increases the assay’s sensitivity comparing to the previous generations. In addition, the detection of IgM antibodies that are present only during the early stages of infection, much shortens the antibody detection “window” period (the period of time in which there is no detectable antibody production), and compare to the second generation, “sandwich” tests could detect antibodies 11 days earlier. To reduce even further the antibody detection “window” period, 4th generation HIV ELISAs that could simultaneously detect HIV antigens (p24) and antibodies have been developed and are commercially available since 1998. With detection of p24, the 4th generation tests shorten the “window” period to 16 days, or compare to the 3rd generation, HIV infection could be detected 8 days earlier.