Dengue-4 false negative results by Panbio® Dengue Early ELISA assay in Brazil.

BACKGROUND: Dengue is a serious public health problem in numerous countries. The ability to rapidly diagnosis dengue is important for patient triage and management. Detection of dengue viral protein, NS1, represents a new approach to dengue diagnosis. OBJECTIVE: The present study aims to evaluate if there are false negative results using the NS1 Ag rapid assay (Panbio(®) Dengue Early ELISA) in two different epidemiological situations (epidemic and non-epidemic). STUDY DESIGN: 220 serum samples from patients with clinical symptoms of classical dengue fever were tested by NS1 antigen capture ELISA and Multiplex-Nested-PCR. RESULTS: In samples collected in a non-epidemic period we found a 100% agreement of ELISA and RT-PCR in dengue negative samples and 85% agreement of ELISA and RT-PCR in dengue positive samples. But when we tested samples during an epidemic period (large DENV-4 outbreak) we found 15% false negative results (p<0.05) in dengue negative samples. CONCLUSIONS: Due to false negative results for DENV-4, the sole use of the Panbio(®) Dengue Early ELISA assay as a screening method for monitoring circulating dengue serotypes must be reevaluated.