Molecular Tests for Dengue Virus
June 14, 2019, Morbidity and Mortality Weekly Report: Dengue and Zika virus diagnostic testing for patients with a clinically compatible illness and risk for infection with both viruses
For symptomatic persons with dengue virus infection, dengue virus RNA can usually be detected by molecular tests for the first 1-7 days in the course of illness.
Nucleic Acid Amplification Test (NAAT)
What is the test?
A NAAT is a generic term referring to molecular tests used to detect viral genomic material. NAAT assays are the preferred method of diagnosis, because they can provide confirmed evidence of infection.
How should it be used and at what time during infection?
- For symptomatic patients during the first 1-7 days of illness, any serum sample should be tested with a NAAT and for IgM antibody since both tests can be performed in serum. Performing both tests can detect more cases than performing just one test.
- After day 7 of illness, few cases can be detected by NAAT.
Specimen types*
- Serum
- Plasma
- Whole blood
- Cerebrospinal fluid
*Serum specimens have been the most extensively validated. The relative sensitivity of serum, plasma, and whole blood is not as well documented. Dengue virus has occasionally been detected in cerebrospinal fluid.
Interpretation of results
- A positive NAAT result confirms dengue virus infection.
- A negative NAAT result does not rule out infection. People with NAAT negative results should be tested for the presence of IgM antibodies against dengue virus to determine possible recent dengue exposure.
- If both the NAAT and IgM antibody results from the acute phase of illness are negative, a convalescent serum should be obtained for IgM antibody testing.
- IgM laboratory unconfirmed case: If a patient with suspected dengue virus infection submits an acute phase specimen that is negative (e.g., by NAAT and/or IgM antibody), and the patient does not submit a convalescent specimen, the patient’s diagnosis is unconfirmed.
Availability (CDC, commercial)
- Commercial diagnostic kits and clinical laboratory NAATs, including the CDC DENV-1-4 multiplex assay, are available in the United States and worldwide and available to Clinical Laboratory Improvement Amendments (CLIA)-certified public health laboratories.
CDC provides reagents and guidance to public health laboratories. CDC also may provide confirmatory testing if requested by public health laboratories.