Positive:
The presence of dengue nonstructural protein 1 (NS1) antigen is consistent with acute-phase infection with dengue virus.
The NS1 antigen is typically detectable within 1 to 2 days following infection and up to 9 days following symptom onset.
NS1 antigen may also be detectable during secondary dengue virus infection, but for a shorter duration of time (1-4 days following symptom onset).
Negative:
The absence of dengue NS1 antigen is consistent with the lack of acute-phase infection.
The NS1 antigen may be negative if specimen is collected immediately following dengue virus infection (<24-48 hours) and is rarely detectable following 9 to 10 days of symptoms.