Antigen Tests for Dengue Virus

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Key points

  • NS1 ELISA testing is recommended to determine dengue infections during the first 7 days of illness.
  • A positive NS1 ELISA test result confirms dengue virus infection without providing serotype information. Indications for use of commercial NS1 ELISA tests and interpretation of positive NS1 ELISA test results may vary.
An image of a pipette dropping a liquid into a test tray.

What the test is

  • NS1 ELISA tests detect the non-structural protein 1 (NS1) of dengue virus.
    • This protein is secreted into the blood during a dengue infection.
  • NS1 ELISA tests have been developed for use in serum and whole blood.
  • Most of these tests use synthetically labeled antibodies to detect dengue NS1 protein.

How NS1 antigen tests should be used and at what time during infection

Overview

  • NS1 is detectable during the acute phase of dengue virus infections.
  • NS1 ELISA tests can be as sensitive as molecular tests during the 7 days of symptoms.
  • NS1 can be detected in some people for several days after symptoms resolve.

Additional Considerations

  • A positive NS1 ELISA 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.
  • In combination, NS1 ELISA and IgM antibody tests can usually provide a diagnostic result during the first 7 days of illness.
    • If results of both tests are negative, a second, convalescent specimen can be tested for IgM to help confirm or rule out infection.

Specimen Type

  • Serum is preferred, though blood and plasma can be used.

Interpretation of results

  • A positive NS1 ELISA test result is indicative of a dengue virus infection.
  • A negative NS1 ELISA test result does not rule out infection.
    • People with negative NS1 and negative or unavailable NAAT test results should be tested for the presence of dengue IgM antibodies to determine possible recent dengue exposure.

Availability

Currently, there is only one dengue NS1 ELISA test approved by the U.S. Food and Drug Administration (FDA). The performance of other commercial dengue NS1 ELISA and rapid diagnostic tests is not well established. These tests are labeled for Research Use Only (RUO) and are not intended for diagnostic procedures. Additionally, no rapid diagnostic tests that include dengue NS1 detection have received FDA approval.

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Content Source:
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)