What Is Dengue NS1 Antigen?

What it is

NS1 is a non-structural protein secreted by the dengue virus. Unlike antibodies, it is a direct viral product, so circulating NS1 supports recent or current dengue infection.

Why it matters

NS1 is detectable from the first day of fever, before IgM antibodies appear — making it the earliest viral antigen marker of acute dengue.

Specimen

Whole blood / serum / plasma

Interpretation

Positive = dengue NS1 antigen detected (acute infection). Negative = below detection limit.

Limitations

Best in the first week; sensitivity varies by serotype; a negative result does not exclude dengue.

Related test: Dengue NS1 Rapid Test — specimen: WB / S / P

Frequently Asked Questions

Is NS1 an antigen or an antibody? NS1 is a viral antigen — a direct viral product, unlike IgM/IgG antibodies.

Related knowledge

• Dengue hub
• Dengue NS1 vs IgM/IgG