Dengue Infection Diagnosis and Management
Interpretation of Dengue IgG Results
- Positive IgG with negative IgM typically indicates past dengue infection, according to the Centers for Disease Control and Prevention (CDC) 1, 2
- Positive IgG with positive IgM suggests a current secondary dengue infection, as recommended by the CDC 1, 3
- When IgG is positive without confirmatory plaque reduction neutralization test (PRNT), it should be interpreted as "presumptive recent flavivirus infection", as stated by the CDC 1, 2
- IgG antibodies can persist for months to years after infection, making them useful markers of previous exposure, as noted by the CDC 2, 4
Diagnostic Algorithm for Dengue
- For patients with symptoms ≤7 days, the CDC recommends performing dengue NS1 antigen test and/or NAAT (nucleic acid amplification test), as well as IgM and IgG antibody testing 1, 5, 6
- For patients with symptoms >7 days, the CDC suggests performing IgM and IgG antibody testing, and considering PRNT for confirmation if available 1, 4, 5
- The interpretation of combined results, as recommended by the CDC, includes:
Common Pitfalls in Interpretation
- Cross-reactivity with other flaviviruses can complicate interpretation of IgG results, as noted by the CDC 1, 3
- Without confirmatory PRNT, positive IgG results should be interpreted cautiously as "presumptive", according to the CDC 1, 2
- A positive IgG test alone cannot determine the timing of infection, as stated by the CDC 1, 2
- IgG tests have limited utility for diagnosis in the acute phase of primary infection, as recommended by the CDC and other guidelines 6
Dengue Infection Interpretation Based on Serological Patterns
Clinical Interpretation and Diagnosis
- The CDC recommends performing PRNT testing against dengue and other endemic flaviviruses for definitive diagnosis, with a PRNT titer ≥10 for dengue and <10 for other flaviviruses confirming past dengue infection 7
- In areas with multiple circulating flaviviruses, epidemiologic data about local virus circulation should be integrated to consider cross-reactivity 7, 8