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Abstract(s)
A hepatite C é um problema de saúde pública e permanece como a principal causa de doença
hepática crónica. O algoritmo de diagnóstico consiste em três testes, determinação de
anticorpos do VHC (VHC Ac) para rastreio, deteção do VHC RNA por PCR em tempo real para
confirmação e determinação do genótipo viral para iniciar o tratamento. Recentemente, foi
desenvolvido um teste para quantificação do antigénio do core do VHC (VHC Ag), permitindo o
diagnóstico serológico da infeção mais precoce durante a fase aguda. Este teste mostrou ser
promissor para diagnosticar a infeção ativa quando comparado aos testes VHC Ac e VHC RNA,
devido à sua especificidade e relação custo/benefício.
Todas as 17 amostras negativas para VHC RNA foram negativas para VHC Ag. Em quatro
amostras com VHC RNA detetável com baixa carga viral (<15 UI/ml) não foi detetado VHC Ag.
Foi determinado o seguinte modelo de regressão linear [VHC Ag] = 0,731.[VHC RNA] - 1,109. A
correlação entre log(VHC Ag) e log(VHC RNA) apresentou um valor de 0,963, permanecendo
igualmente forte acima do limiar de 3000 UI/mL (r = 0,948). O menor valor de VHC RNA
quantificado (20,3 UI/ml) corresponde a um valor de VHC Ag de 5,49 fmol/L. A presença de
VHC Ac foi previamente detetada em 43 das 59 amostras e não mostrou ter relevância clínica
para o diagnóstico da infeção. Para 16 pacientes, não há informação sobre a sua pesquisa.
Tanto o genótipo como o género não demostraram ter influência nos valores de VHC RNA e de
VHC Ag.
O teste VHC Ag demonstrou elevada concordância com o teste VHC RNA, apresentando 100%
de especificidade e 88,1% de sensibilidade analítica. O teste VHC Ag diminuiu a sua
sensibilidade para valores de VHC RNA inferiores a 3000 UI/mL, sendo necessário recorrer à
confirmação pelo teste VHC RNA. Os resultados do VHC Ag podem ser emitidos no prazo de 2
a 3 dias vs até 2 semanas para resultados de PCR em tempo real devido à necessidade de
amostras em lote por razões de custo-efetividade, permitindo um diagnóstico precoce e o
início da terapia. Os dados deste estudo mostram que o teste VHC Ag pode simplificar o
diagnóstico e monitorização da infeção pelo VHC.
Hepatitis C is a public health problem as it remains the major cause of chronic liver disease. The diagnostic algorithm consists of three tests, HCV antibody test (HCV Ac) for screening, HCV RNA detection by real-time PCR for confirmation and determination of the viral genotype to initiate the treatment. Recently, a test for quantification of HCV core antigen (HCV Ag) was developed, allowing the serologic diagnostic of infection during acute phase. This test has shown to be promising to diagnose active infection when compared to HCV Ac and HCV RNA since it is specific, less expensive and cost-effective. All 17 negative HCV RNA samples were negative for HCV Ag. In four HCV RNA positive sample with low viral load (<15 IU/ml) no HCV Ag was detected. The following linear regression model was determined [HCV Ag] = 0,731.[HCV RNA]- 1,109. The correlation between log(HCV Ag) and log(HCV RNA) yielded a value of 0,963, equally strong above the threshold 3000 IU/mL (r=0,948). The lowest HCV RNA quantification (20,3 IU/ml) yielded an HCV Ag quantification of 5.49 fmol/L. HCV Ac previously tested positive in 43 of the 59 samples and was not shown to be clinically relevant for the diagnosis of the infection. For 16 patients there was no information on HCV Ac status. HCV RNA and HCV Ag did not show differences between genotypes or between genders. The HCV Ag test showed high concordance with RNA, demonstrating 100% specificity and 88,1% of analytical sensibility. The HCV Ag test reduced its sensitivity to HCV RNA values below 3000 IU/mL, and it was necessary to use the HCV RNA test as a confirmatory test. HCV Ag results can be issued within 2-3 days vs up to two weeks for real-time PCR results due to the necessity to batch samples for cost-effectiveness, enabling an earlier diagnosis and initiation of therapy. This study data show that HCV Ag test may be a simple and affordable tool for diagnosis and monitoring of HCV infection.
Hepatitis C is a public health problem as it remains the major cause of chronic liver disease. The diagnostic algorithm consists of three tests, HCV antibody test (HCV Ac) for screening, HCV RNA detection by real-time PCR for confirmation and determination of the viral genotype to initiate the treatment. Recently, a test for quantification of HCV core antigen (HCV Ag) was developed, allowing the serologic diagnostic of infection during acute phase. This test has shown to be promising to diagnose active infection when compared to HCV Ac and HCV RNA since it is specific, less expensive and cost-effective. All 17 negative HCV RNA samples were negative for HCV Ag. In four HCV RNA positive sample with low viral load (<15 IU/ml) no HCV Ag was detected. The following linear regression model was determined [HCV Ag] = 0,731.[HCV RNA]- 1,109. The correlation between log(HCV Ag) and log(HCV RNA) yielded a value of 0,963, equally strong above the threshold 3000 IU/mL (r=0,948). The lowest HCV RNA quantification (20,3 IU/ml) yielded an HCV Ag quantification of 5.49 fmol/L. HCV Ac previously tested positive in 43 of the 59 samples and was not shown to be clinically relevant for the diagnosis of the infection. For 16 patients there was no information on HCV Ac status. HCV RNA and HCV Ag did not show differences between genotypes or between genders. The HCV Ag test showed high concordance with RNA, demonstrating 100% specificity and 88,1% of analytical sensibility. The HCV Ag test reduced its sensitivity to HCV RNA values below 3000 IU/mL, and it was necessary to use the HCV RNA test as a confirmatory test. HCV Ag results can be issued within 2-3 days vs up to two weeks for real-time PCR results due to the necessity to batch samples for cost-effectiveness, enabling an earlier diagnosis and initiation of therapy. This study data show that HCV Ag test may be a simple and affordable tool for diagnosis and monitoring of HCV infection.
Description
Keywords
Algoritmo de Diagnóstico Antigénio do Core Carga Viral Vírus da Hepatite C