Dengue NS1 antigen

What it measures

Detects the non-structural protein 1 secreted by dengue virus into blood. It allows early diagnosis in the first 1–5 days of fever, before antibodies appear.

Specimen and preparation

• Specimen: Serum or plasma
• Tube: Gold top
• Preparation: Best collected in days 1–5 of fever.

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• Acute dengue infection (any of the 4 serotypes)
• Positivity may persist to about day 7–9
• Higher positivity in primary than secondary infection

Method

Immunochromatographic rapid test or ELISA

Good to know

Sensitivity falls after day 5 and in secondary infection; a negative NS1 late in illness does not exclude dengue.

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