Comparison of a rapid immuno-chromatography assay with a standard ELISA for the detection of IgM and IgG antibodies against dengue viruses.

A total of 765 blood samples collected from dengue suspected patients admitted to a Teaching Hospital in Sri Lanka were used to compare a rapid ICT assay with a standard ELISA for the detection of anti-dengue virus (DENV) IgM and IgG. Detection accuracy indices including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), Chi square and Cohen's kappa values were determined for the ICT assay using the ELISA as a comparator for the detection of anti-DENV IgM and IgG. The rapid ICT assay showed a sensitivity of 64%, specificity of 75%, NPV of 68% and PPV of 72% for anti-DENV IgM detection. However, all the accuracy indices were relatively higher for the anti-DENV IgG detection by the ICT assay than those for anti-DENV IgM detection. Despite the low sensitivity for anti-DENV IgM detection by the ICT assay, considering the limitations in using ELISAs in resource limited regions, rapid ICT assays would be useful for the detection of more recent DENV infections. As many patients present after fever days 5 in the study area, anti-DENV IgM/IgG would be the suitable marker to be detected by rapid ICT assays in such areas.