Significance of NS1 detection:
  • Detected in acute phase.
  • Lessens the window period of detection since can be detected after 1 day after onset of symptoms even before IgM appears.
  • In addition to early diagnosis, NS1 Ag may be an indicator of disease severity. A very high concentration of NS1Antigen within 72 hrs. of illness identifies patients at risk of developing DHF or DSS.
  • No cross reaction with other flaviviruses.

NS1 antigen can be detected in both primary and secondary infection.