Dengue virus IgG
Looks for IgG antibodies that show whether your immune system has met a dengue virus before, but it cannot date the infection.
AI-verified against cited sources. Awaiting expert reviewAlso called DENV IgG, Dengue Ab IgGLOINC 29676-4
What it is
Dengue is a mosquito-borne virus with four related types. After an infection, the body makes IgM antibodies first and IgG antibodies later. This test looks for the IgG antibodies. A positive result means your blood has antibodies that react with dengue virus, which usually points to an infection at some time in the past. The result is printed as positive, negative or equivocal, sometimes with an index number.
Why it matters
IgG helps show whether someone has been exposed to dengue before. That matters because a second dengue infection carries a higher risk of severe dengue than a first one (WHO). IgG is also used in population surveys and to tell a first infection from a repeat one. CDC does not recommend a single IgG result to diagnose a current illness.
If it’s low
A negative result means no dengue IgG was found, so you most likely have not been infected before. It can also be negative early in a first infection, before IgG has formed, so it cannot rule out a current illness.
Common causes
- Never having been infected with dengue
- Testing early in a first infection, before IgG appears
What can help
- If you are ill now, ask about NS1, PCR or IgM testing instead
- Ask about mosquito-bite protection if you live in or travel to a dengue area
If it’s high
A positive result means IgG antibodies that react with dengue virus were found. This usually means you were infected at some point in the past, sometimes without symptoms. It does not show when, and antibodies to related viruses can also make this test positive. It does not prove you are sick now.
Common causes
- A past dengue infection, including one that caused no symptoms
- A recent dengue infection, if a second sample taken after symptoms settle shows a change from negative to positive
- Past infection with a related flavivirus, such as Zika, which can cause cross-reacting antibodies
What can help
- Ask whether a positive IgG changes what you should do if you get a fever in a dengue area
- Ask whether PCR, NS1 or IgM testing is needed if you are ill now
- Ask about steps to avoid mosquito bites in areas where dengue spreads
What can affect your result
- Past infections: IgG can stay positive for years after infection
- Related viruses: Zika, West Nile, yellow fever and Japanese encephalitis viruses can cause cross-reacting results
- Day of illness: in the first days of a first infection, IgG is often not yet detectable
- The assay: different kits use different cut-offs, so numbers are not comparable between labs
- Antibody tests can react with antibodies from other flaviviruses, such as Zika, West Nile or yellow fever, so a positive result does not prove a past dengue infection.
- A single IgG result cannot tell you when the infection happened. It may reflect dengue or another flavivirus infection long ago (CDC).
- Each lab uses its own kit, scale and cut-offs, so an index or ratio printed by one lab cannot be compared with another's.
IgG appears later than IgM and, once positive, can stay detectable for years after a dengue infection.
When to talk to a clinician
If you have a fever and live in or recently traveled to a dengue area, contact a clinician, whatever this result says. Go to urgent care or an emergency department right away for warning signs such as severe belly pain, vomiting that will not stop, rapid breathing, bleeding gums or nose, blood in vomit or stool, extreme thirst, pale or cold skin, restlessness or marked weakness.
Questions you could ask
- Do I need IgM, NS1 or PCR testing as well, given my symptoms and travel?
- Could this positive be from a past dengue infection or a related virus?
- If I get a fever in a dengue area, which tests should I ask for?
- Since I have no sign of past infection, how can I best protect myself when traveling?
Questions people ask
Does a positive dengue IgG mean I have dengue now?
Not on its own. A positive IgG usually shows an infection at some time in the past, and it can also be caused by related viruses. If you are ill now, doctors use NS1, PCR or IgM tests, or compare two samples taken some days apart.
Why does a past dengue infection matter?
A person can be infected with dengue more than once, because there are four types. WHO says people infected for the second time are at greater risk of severe dengue. That is why a past infection is worth mentioning to your clinician if you get a fever in a dengue area.
Show the science and sources
For clinicians and researchers
Dengue IgG is typically measured by ELISA or other immunoassays. CDC states that IgG in a single specimen is not recommended to diagnose acute dengue, because it may detect antibodies from dengue or other flavivirus infections in the past, while a negative-to-positive IgG conversion in paired samples (the first within 7 days of illness, the second after symptoms subside) indicates a recent infection. A 2026 review notes IgG-ELISA is used mainly to separate primary from secondary dengue and for seroepidemiology, not for definitive acute diagnosis. Serologic assays cross-react with other flaviviruses, whereas NS1 and NAAT tests do not (CDC), and plaque reduction neutralization tests (PRNT) can help resolve false-positive IgM results caused by non-specific reactivity, although PRNT may not confirm a significant share of IgM-positive results where dengue and Zika neutralizing antibodies are common (CDC). A second infection with a different type raises the risk of severe dengue (WHO). Result LOINC codes vary by lab and kit: 29676-4 and 29661-6 for presence, 23958-2 for units, 100965-3 for interpretation.
LOINC 29676-4 (primary), 29661-6, 23958-2, 109954-8, 100965-3. Specimen: serum.
Sources
- Testing and Diagnosis of Dengue (clinical guidance), Centers for Disease Control and Prevention
- About Dengue, Centers for Disease Control and Prevention
- Dengue and severe dengue, World Health Organization
- History, Virology, Pathogenesis, Epidemiology, and Laboratory Diagnosis of Dengue Virus: A Focused Review, Cureus (2026)
- LOINC codes verified with the NLM Clinical Tables LOINC search (e.g. 29676-4), U.S. National Library of Medicine
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.