Key words: HIV screening kit, window period, p24antigen, enzyme-linked fluorescent assay

Key words: HIV screening kit, window period, p24antigen, enzyme-linked fluorescent assay

Fig.1 @ A principle of assay The assay comprises of two reactions. The first reaction, for the detection of anti-hiv- 1and anti-hiv-2igg, is performed in the lower part of the solid-phase receptacle (SPR), which is coated with synthetic peptides (gp41and gp36). Anti-human IgG labelled with alkaline phosphatase is used as the conjugate. The second reaction, for the detection of p24ag, is performed in the upper part of the SPR, which is coated with monoclonal anti-p24antibodies. During incubation, p24ag is released through virus lysis and binds to the monoclonal antibodies on the SPR and also to the biotinylated anti-p24antibodies. The antibody-ag-antibody complex binds to the alkaline phosphatase-labelled streptavidin. The final detection step is the same for both reactions. The substrate (4-methylumbelliferyl phosphate) is catalyzed by the conjugate into a fluorescent product (4-methylumbelliferone). Table1 @ Comparison of the results of VIDAS HIV DUO, VIDAS HIV1/2IgG, Enzygnost Anti- HIV 1/2Plus and GENEDIA HIV1/2Mix in HIV seropositive specimens from Japan and Cameroon

Table2 @ Comparison of the results of VIDAS HIV DUO, VIDAS HIV1/2IgG, Enzygnost Anti-HIV1/2Plus, GENEDIA HIV1/2Mix and Abbott HIV1/2in anti-hiv1mixed Titer PERFORMANCE Panel (BBI Lot#PRB202)

Table3 @ Comparison of the results of VIDAS HIV DUO, VIDAS HIV1/2IgG, Enzygnost Anti-HIV1/2Plus, GENEDIA HIV1/2Mix and Abbott HIV1/2in anti-hiv2mixed Titer PERFORMANCE Panel (BBI Lot#PRF301B)

Table5 @ Comparison of the results of VIDAS HIV DUO, VIDAS HIV1/2IgG and GENEDIA HIV1/2 Mix in specimens from Kanagawa prefectural public health centers

agglutination test for the human immunodeficiency virus antibody: A comparative study with enzyme-linked immunosorbent assay and immuno-fluorescence. J pn J Cancer Res (Gann) 1986; 77: 1211-1213. generation human immunodeficiency virus scre- assays. J Clin Microbiol1998; 36 ening (8) 2235-2239. 8) Mulder J, Mckinney N, Christopherson C, Snin- sky J, Greenfield L, Kwok S: Rapid and simple PCR assay for quantitation of human immunode- ficiency virus type1rna in plasma: application to acute retro-viral infection. J Clin Microbiol 1994; 32 (2): 292-300. 6) Bernard W, El HFM, Annemarie B, Hans WD: Reduction of diagnostic window by new fourth Evaluation of a New Screening Assay Kit for The Combined Detection of HIV p24antigen and Antibody \ Comparison of the Performance of the New Kit and HIV Antibody AssayKits \ Takako HAYASHI, Sumi WATANABE, Makiko KONDO, Takayuki SAITO and Mitsunobu IMAI Department of Virology, Kanagawa Prefectural Public Health Laboratory DUO is an automated HIV infection screening test kit based on the combined detection of p24 Ag and anti-hiv-1 and anti-hiv-2igg in human sera or plasma using the ELFA technique (Enzyme- Linked Fluorescent Assay). The performance of DUO was compared with that of HIV-1/HIV-23rd generation EIA plus and particle agglutination (PA) test. A total of141seropositive sera,3seroconversion panels, 300seronegative sera and387potentially cross-reactive serum samples weretested. One hundred and forty one seropositive sera in Japan and Cameroon were all positive with DUO. Three seroconversion panels (panel Q, Z, AE) were tested to evaluate sensitivity. In Panel Q, infecution was detected seven days earlier with DUO than with the 3rd generation EIA plus and PA. In Panel AE, infection was detected four days earlier with DUO thanwith the single antibody assays. Three hundred seronegative sera from Kanagawa prefectural public health centers were all negative with DUO as well as PA test. Three hundred and eighty seven potentially cross-reacting samples were tested to challenge the specificity of the assay. These included samples from pregnant women and hepatitis patients. In four of the204samples from pregnant women, false-positive results were observed with DUO. In three of the183samples from hepatitis patients, false-positive results were also obtained with DUO. All samples of7duo positive results were negative with western blot test. Five of them were negative with RT-PCR and2of them were nottested because there were not enough samples. Thirty cross-reacting (false-positive) samples by PA test from blood donors were tested by DUO, and all of these were negative by DUO.