Document 2704
 DOCN  M94A2704
 TI    Western-blot--does it really help as a confirmatory test in a developing
       country?
 DT    9412
 AU    Buchalter M; Schneider EZ; Nottar VL; Barcellos NT; Ramos MC; Ferreira
       JT; Balsan AM; Willers DM; Goncalves JE; Mondini LG; et al;
       IPB--SSDT/AIDS--Rio Grande do sul State Health Secretariat, Porto;
       Alegre, Brazil.
 SO    Int Conf AIDS. 1994 Aug 7-12;10(1):243 (abstract no. PB0402). Unique
       Identifier : AIDSLINE ICA10/94369871
 AB    OBJECTIVE: To evaluate the resolution of the Western-blot as a
       confirmatory test in addition to the indirect immunofluorescence,
       through a retrospective study of the laboratory records. METHODS: As a
       routine, HIV-1 recombinant ELISA is used as a screening test. When
       positive, the sample is tested with a competitive ELISA and Indirect
       Immunofluorescence--IFI (Fundacao Osvaldo Cruz-Ministerio de Saude). In
       case of negative or inconclusive IFI results, a Western-blot is
       performed. If the Western-blot is negative or inconclusive a new sample
       is collected after three months for retesting. Since 1990, approximately
       20,000 HIV tests were performed at the Central State Public Health
       Laboratory (Instituto de Pesquisas Biologicas). The samples come from
       alternative anonymous test sites, STD clinics, blood banks, hospitals or
       penitentiaries. RESULTS: 98% of the samples with a first ELISA positive
       are confirmed through the subsequent tests, the remaining 2% present IFI
       negative or indeterminate results. In a total of 73 samples with at
       least one positive ELISA and a negative or inconclusive IFI were tested
       with a Western-blot (Dupont, Sorin or Pasteur), using the CDCs criteria
       for positivity. Out of these samples, only 23 (31.5%) were positive. Out
       of the remaining 50 (68.5% of the total), 34 (68.0%) were inconclusive
       and 16 (32.0%) were negative. CONCLUSION: Considering the high cost of
       the Western-blot and the low index of resolution for the IFI negatives
       or indeterminate cases--about 70% of them having to collect new
       sample--we question the validity of including the Western-blot in the
       diagnostic flowcharts for public health purposes.
 DE    *AIDS Serodiagnosis  *Blotting, Western  Brazil  Comparative Study
       *Developing Countries  Fluorescent Antibody Technique  Human  HIV
       Antibodies/BLOOD  HIV Seropositivity/*DIAGNOSIS/IMMUNOLOGY
       HIV-1/*IMMUNOLOGY  Predictive Value of Tests  Retrospective Studies
       MEETING ABSTRACT

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