Serodiagnosis of dengue virus infection using commercially available antibody and NS1 antigen ELISAs

- Detection of DENV NS1 antigen is sensitive for acute cases of DENV infection.
- Evaluation for DENV NS1 and DENV IgM/IgG does not improve sensitivity over NS1 alone.
- False positives are more common with anti-DENV IgG than DENV NS1 or anti-DENV IgM.

Accuracy of the InBios DENV Detect IgM, IgG and NS1 antigen (Ag) ELISAs (Seattle, WA) for detection of dengue virus (DENV) infection were evaluated using 100 retrospectively selected sera from acutely febrile patients presenting to a Singapore hospital. The InBios DENV NS1, IgM and IgG ELISAs had an overall sensitivity of 83.6%, 40% and 58.2% and an overall specificity of 97.8%, 97.8% and 55.6%, respectively. Simultaneous testing for NS1 and IgM-antibodies yielded a sensitivity and specificity of 85.5% and 95.5%, respectively, which did not significantly differ from testing for NS1 Ag alone. Using sera positive for IgM- or IgG-class antibodies to six common arboviruses, the InBios IgM and IgG ELISAs showed an overall analytic specificity of 89.2% and 66.4%, respectively. This study suggests that recent DENV infection can reliably be detected by the InBios NS1 Ag ELISA alone and that InBios DENV IgG reactivity should be interpreted with caution.