Evaluation of laboratory assays for screening antibody to hepatitis C virus

Abstract

An evaluation study, involving 11 screening methods for the detection of antibody to hepatitis C virus (anti-HCV) and a panel of 500 serum samples, was performed. Samples were tested by all 11 methods, and those showing reactivity in at least one method were studied by a combination of supplemental assays (recombinant immunoblot assays, first and second generation; neutralization test for anti-c100; synthetic peptide immunoblot assay; recombinant multi-dot immunoassay) and classified as positive (110 samples), indeterminate (4 samples), or negative (386 samples) on the basis of the results obtained. Second-generation recombinant methods performed better on positive samples than first-generation assays or synthetic peptide-based methods (99.1-100% correlation vs. 64.5-85.5% and 93.6-99.1%, respectively), whereas the latter showed higher correlations on negative samples than recombinant assays (97.4-99.7% vs. 82.4-93%). Further investigations, using broad panels of indeterminate samples from blood donors, should be done, however, before synthetic peptide-based methods are recommended for blood bank screening. Reactivity of samples must be confirmed by one supplemental test in all cases before the donor is informed. In some cases, it may require the use of two or more different tests to obtain definite conclusions.

Sensitivity of a modified version of the ARCHITECT® Anti-HCV test in detecting samples with immunoblot-confirmed, low-level antibody to hepatitis C virus

“…In addition, dilution series from high-titre anti-HCV positive samples are also unlikely to provide useful results since the natural reduction of antibody against the different viral antigens is not accurately represented by serial dilution. The use of panels of individual serum samples displaying low anti-HCV levels, although labour intensive, is more likely to provide more accurate information (León et al, 1993).…”

Relevance of Reactivity in Commercially Available Hepatitis C Virus Antibody Assays

“…However, we have no evidence that underlying immunosuppression was the cause of a weak immune response in those 35 patients with indeterminate test results. Single bands in confirmatory assays using recombinant proteins or unconfirmed low MEIA reactivities may be caused by antibodies against the microorganism used for cloning and expression (10). Thus, synthetic peptides have been described to be more specific, but unfortunately they have proven to be less sensitive (3,10).…”

“…Single bands in confirmatory assays using recombinant proteins or unconfirmed low MEIA reactivities may be caused by antibodies against the microorganism used for cloning and expression (10). Thus, synthetic peptides have been described to be more specific, but unfortunately they have proven to be less sensitive (3,10). High levels of immunoglobulin G may lead to nonspecific binding of the Fc fragment to the solid phase, resulting in false reactivity in a screening assay.…”

Diagnóstico da hepatite C na prática médica: revisão da literatura

“…Destaca-se o aumento da sensibilidade e a redução na taxa de falso-positivos a partir da primeira geração. Entretanto, os testes ELISA não detectam todas as pessoas infectadas com o VHC (4, 22-25) e, como não há padronização na produção de antígenos entre os vários fabricantes, os resultados podem variar, principalmente em grupos com baixo risco de infecção (26,27).…”