Serological Testing for Distant Dengue History
Yes, serology can detect a distant history of dengue infection through IgG antibody testing, which persists for months to years after infection, but it cannot determine the specific timing of that past infection. 1
Understanding Antibody Persistence
- IgG antibodies develop around day 5-7 in primary dengue infections and persist for months to years, making them the marker of choice for detecting past infection 1
- IgM antibodies typically appear 3-5 days after symptom onset but can persist for months after the initial infection, which complicates interpretation of timing 1
- The presence of IgG alone (without IgM) generally indicates a past infection that occurred beyond the typical IgM detection window 1
Diagnostic Limitations and Cross-Reactivity
- IgM and IgG antibodies can cross-react with other flaviviruses (West Nile, yellow fever, Japanese encephalitis, Zika), potentially causing false-positive results 1, 2
- In areas with multiple circulating flaviviruses, a positive IgG result should be interpreted as "presumptive flavivirus infection" rather than definitive dengue unless confirmatory testing is performed 3
- For definitive diagnosis of past dengue infection, plaque reduction neutralization tests (PRNTs) against dengue and other endemic flaviviruses are required, with a PRNT titer ≥10 for dengue and <10 for other flaviviruses confirming past dengue infection 1
Testing Algorithm for Distant History
- Order dengue IgG antibody testing as the initial test for patients inquiring about distant past infection 1
- If IgG is positive and definitive confirmation is needed (especially in areas with other flaviviruses), perform confirmatory PRNT testing against dengue and other endemic flaviviruses 1
- Document complete vaccination history for flaviviruses (yellow fever, Japanese encephalitis, tick-borne encephalitis) to interpret cross-reactivity 4
Critical Caveats
- Serology cannot determine the specific timing of past infection—only that infection occurred at some point, as IgG persists indefinitely 3, 1
- In secondary flavivirus infections, neutralizing antibodies against multiple flaviviruses rise rapidly, potentially precluding conclusive determination of which specific virus caused past infection 4
- A positive IgG alone does not confirm acute infection; it only indicates past exposure 4
- The positive predictive value of serological testing is lower in areas with low dengue prevalence but high prevalence of other flaviviruses 1