Nucleic acid amplification tests (NAATs) can detect dengue virus during the first 7 days of illness. CDC's DENV-1-4 Real-Time RT-PCR Assay is one — it both detects dengue virus and identifies its serotype. The Food and Drug Administration has approved it for in vitro diagnosis of dengue, and CDC distributes it to laboratories.
Image from CDC's page on the DENV-1-4 RT-PCR assay
What it is
The assay finds dengue virus serotypes 1, 2, 3 or 4 in serum or plasma from people with suspected, symptomatic dengue, mild or severe. The kit contains:
- primers and probes for qualitative detection of each serotype;
- a positive control mix of heat-inactivated viruses of all four serotypes;
- a human specimen control — noninfectious cultured human cell material that shows RNA was recovered successfully.
It can run in singleplex format (one serotype per reaction) or multiplex (all four in one reaction), with equal sensitivity.
What it is for
On an Applied Biosystems 7500 Fast Dx Real-Time PCR instrument, it is used to:
- diagnose dengue in patients with consistent signs and symptoms;
- identify the serotype from viral RNA in serum or plasma;
- provide surveillance information on which dengue viruses are circulating.
Two limits: use it on specimens taken within 7 days of symptom onset — and it is not approved for screening blood or plasma donors.
Reading the results
| Result | Meaning |
|---|---|
| Positive | confirmed current dengue infection |
| Negative | does not rule out dengue |
| Sample taken 7 or more days after symptoms began | test for IgM antibodies to dengue instead — they can stay detectable for 3 months or more |
Who can get it
CDC distributes the assay to laboratories whose staff are trained and experienced in standardized molecular diagnostic testing and viral diagnosis, with proper biosafety equipment and containment. In the United States it must be used only with ancillary reagent lots qualified by CDC's Dengue Branch, such as specified RT-PCR enzyme and RNA extraction kits; any other lots may affect performance. For international laboratories, kits are labeled Research Use Only and intended for surveillance. Laboratories order kits and get technical support from the Dengue Branch.
Sources
Based on "CDC DENV-1-4 Real-Time RT-PCR Assay," Centers for Disease Control and Prevention; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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