What should you know about the dengue antigen NS1 test?

NS1 is a protein released by the dengue virus during infection. Detecting it can support a diagnosis of dengue, especially early in the illness. A negative result does not always exclude dengue: timing, sample quality and the test method affect interpretation. Clinicians may consider other tests or repeat testing when symptoms and exposure history still suggest dengue. The result does not by itself show how severe the illness will become.

Arrange a [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) and describe when fever began, recent travel and mosquito exposure. The clinician may request the NS1 test with other blood investigations and will interpret the result with examination findings. While waiting, rest, drink fluids if able, avoid medicines your clinician has not approved, and prevent further mosquito bites.

Get urgent help for severe abdominal pain, repeated vomiting, bleeding or [Easy Bruising](/symptoms/easy-bruising/), faintness, confusion, breathing difficulty, or inability to drink. A persistent [Fever](/symptoms/fever/) with [Chills](/symptoms/chills/) or worsening [Muscle Aches](/symptoms/muscle-aches/) needs prompt review, regardless of an earlier test result.

Ask whether the test timing fits your illness, whether another test is needed, how the result changes your care, and which warning signs should trigger emergency assessment.