EVALUATION OF A RAPID IMMUNOCHROMATOGRAPHIC TEST FOR DIAGNOSIS OF DENGUE VIRUS-INFECTION

A rapid (<7-min) immunochromatographic test for immunoglobulin M (IgM) and IgG antibodies to dengue viruses was evaluated by using hospital admission and discharge sera from 124 patients, The reference laborato ry diagnosis was based on the results of virus isolation, hemagglutina tion-inhibition assay (HAI), and enzyme immunoassay (EIA), By the stan dard assays, patients experienced primary dengue virus infection (n = 30), secondary dengue virus infection (n = 48), Japanese encephalitis (JE) virus infection (n = 20), or no flavivirus infection (n = 26), Th e rapid test demonstrated 100% sensitivity in the diagnosis of dengue virus infection and was able to distinguish between primary and second ary dengue virus infections through the separate determinations of IgM and IgG, For all patients with primary dengue virus infection a posit ive test for IgM to dengue virus and a negative test for IgG to dengue virus were obtained, whereas for 46 of 48 patients (96%) with seconda ry dengue virus infection, a positive test for IgG to dengue virus wit h or without a positive test for IgM to dengue virus was obtained, The remaining two patients with secondary dengue virus infection had posi tive IgM test results and negative IgG test results. Furthermore, the rapid test was positive for patients confirmed to be infected,vith dif ferent dengue virus serotypes (12 infected with dengue virus serotype 1, 4 infected with dengue virus serotype 2, 3 infected with dengue vir us serotype 3, and 2 infected,vith dengue virus serotype 4), The speci ficity of the test for nonflavivirus infections was 88% (3 of 26 posit ive), while for JE virus infections the specificity of the test was on ly 50% (10 of 20), However, most patients with secondary dengue virus infection were positive for both IgM and IgG antibodies to dengue viru s, while no patients with JE virus infection had this profile, so cros s-reactivity was only a concern for a small proportion of patients wit h secondary dengue infections, The rapid test demonstrated a good corr elation,vith the reference EIA and HAI and should be useful for the ra pid diagnosis of dengue virus infections.