Dengue Virus Antigen Detection
What is the test?
- NS1 tests detect the non-structural protein NS1 of dengue virus. This protein is secreted into the blood during dengue infection.
- NS1 tests have been developed for use in serum. Most of these tests use synthetically labeled antibodies to detect dengue NS1 protein.
How should it be used and at what time during infection?
- NS1 is detectable during the acute phase of dengue virus infections. NS1 tests can be as sensitive as molecular tests during the first 0-7 days of symptoms. After day 7, NS1 tests are not recommended.
- A positive NS1 test result is indicative of a dengue infection but does not provide serotype information. Knowing the serotype of the infecting virus is not necessary for patient care; however, if serotype information is needed for surveillance purposes, the sample should be tested by NAT.
- Though studies show that NS1 can be found in whole blood or plasma, most NS1 tests have been developed and evaluated in serum samples. While combined testing with a NS1 and IgM antibody test can usually provide a diagnostic result during the first 1-7 days of illness, a second, convalescent phase specimen should be obtained and tested for IgM when both antigen and antibody tests are negative.
Interpretation of results
- A positive NS1 test result confirms dengue virus infection without providing serotype information.
- A negative NS1 test result does not rule out infection. People with negative NS1 results should be tested for the presence of dengue IgM antibodies to determine possible recent dengue exposure.
Dengue NS1 tests are available as commercial diagnostic kits, a limited number are cleared by the US Food and Drug Administration. Some public health and commercial laboratories use these tests.