Evaluation of six immunoassays for detection of dengue virus-specific immunoglobulin M and G antibodies

The performance of six commercially available immunoassay systems for the d etection of dengue virus-specific immunoglobulin M (IgM) and IgG antibodies in serum was evaluated. These included two IgM and IgG enzyme immunoassays (EIA) from MRL Laboratories and PanBio, a rapid immunochromatographic test (RIT) from PanBio, immunofluorescence assays (IFA) from Progen, a dot blot assay from Genelabs, and a dipstick EIA from Integrated Diagnostics (INDX) . For this study a panel of 132 serum samples, including 90 serum samples f rom patients with suspected dengue virus infection and 42 serum samples fro m patients with other viral infections, was used. In addition, serial serum samples from two monkeys experimentally immunized and challenged with degr ee virus type 2 were used. Results were considered conclusive when concorda nt results were obtained with four of the six antibody-specific assays. Bas ed on this definition, the calculated overall agreement for the human serum samples for the respective IgM immunoassays was 97% (128 of 132), with 34% (45 of 132) positive serum samples, 63% (83 of 132) negative samples, and 3% of samples (4 of 132) showing discordant results. The calculated overall agreement for the IgG assays was 94% (124 of 132), with 49% (65 of 132) po sitive, 45% (59 of 132) negative, and 6% (8 of 132) discordant results, res pectively. The sensitivities of the dengue virus-specific assays evaluated varied between 71 and 100% for IgM and between 52 and 100% for IgG, with sp ecificities of 86 to 96% and 81 to 100%, respectively. The relative sensiti vities of the respective IgM assays measured with the monkey serum samples were comparable with those obtained with 12 serial serum samples from human s. Overall performance, based on the sum of the agreement, sensitivity, spe cificity, and Kappa statistics of the IgM and IgG immunoassays, showed that the antibody detection systems from INDX and Genelabs and the MRL and PanB io EIA are useful and reliable assays for dengue virus serodiagnosis.