Dengue NS1 Antigen

When is the best time to test after fever starts?

NS1 antigen is most reliable within the first 5 days of fever, while IgM antibodies become more detectable from day 4 or 5 onward — testing too early or too late in the illness can affect which markers show up positive.

What does a positive IgG alone mean?

If NS1 and IgM are negative but IgG is positive, it usually indicates a past dengue infection rather than a current one.

Is a repeat test ever needed?

Yes, if initial results are negative but dengue is still strongly suspected based on symptoms, your doctor may recommend repeating the test a few days later as antibody levels rise.