Objective: Dengue is a re-emerging public health problem threatening the tropical developing world, mandating rapid diagnosis and supportive management in the absence of licensed vaccines or anti-dengue therapy. Regions endemic to dengue and related viruses are overwhelmed by the sudden surge of cases during outbreaks. It is difficult to justify confirmatory diagnosis of every case using The World Health Organization (WHO) criteria or differentiate it from other concurrent viral illnesses. The study evaluated a rapid, sensitive and specific diagnostic methodology suitable for dengue outbreaks in resource-limited facilities.
Methods: There were one hundred dengue patients as per WHO Criteria, as well as 100 healthy controls from New Delhi, India, were included. Samples collected on the fifth day of onset of fever were tested by lateral flow immunochromatography (LF-ICT), IgM ELISA and reverse transcriptase polymerase chain reaction (RT-PCR) and results were compared. Diagnostic accuracy indices and Kappa analysis were calculated.
Results: The sensitivity, specificity, positive and negative predictive values (PPV and NPV) of non-structural protein 1 (NS1) against RT-PCR was 98.31%, 100%, 100%, 99.3% and strength of agreement was good.
Conclusion: Antigen-based and molecular tests are a better tool for early diagnosis of dengue. The combined LF-ICT kits are highly sensitive, specific, user-friendly, compact, frugal and thus recommended for use in dengue outbreaks, field conditions and as bed-side diagnostic tests, for confirmatory dengue diagnosis. Further studies are required to assess their utility in prognosis, surveillance and establishment of guidelines for dengue outbreaks.