Antigen sandwich elisa predicts RT-PCR detection of dengue virus genome in infected culture fluids of aedes albopictus C6/36 cells.

Antigen detection by sandwich ELISA was evaluaated to predict RT-PCR detection of dengue viral genome in infected culture fluid of Aedes albopictus clone C6/36 cells. Serum specimens collected from dengue patients within five days from onset of fever in two hospitals in Metro Manila, Philippine, were inoculated into C6/36 cells incubated at 28 C.A total of 282 infected culture fluid specimens were harvested and examined by sandwich ELISA and RT-PCR to detect dengue viral antigen and genome respectively. In the sandwich ELISA, the P/N ratio was calculated by dividing optical density (OD) of a given test specimen by the OD of the standard negative specimen. Samples with a P/N ratio > 4.001 were positive for viral genome detection by RT-PCR. The sensitivity and specificity of antigen sandwich ELISA with RT-PCR as the standard were 90.4% and 100% respectively. Although antigen sandwich ELISA is less sensitive than RT-PCR, its usefulness lies in its capability to screen a large number of samples at a minimum cost, especially during an outbreak. Samples that meet a set cutoff value can undergo confirmation of RT-PCR for further epidemiological studies.