Finding the right tests…
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Finding the right tests…
Serology
DENGUE IgG checks your blood for a longer-lasting antibody that shows you've been exposed to dengue at some point in your life, not necessarily recently. A single IgG sample can't tell your doctor whether that exposure was last week or years ago, which is why it isn't used alone to diagnose a current infection. Confirming a genuinely recent infection with IgG needs two samples taken roughly two weeks apart, checking whether the level has gone from negative to positive or risen sharply — a pattern called seroconversion. Doctors most often order this alongside an IgM test, since reading the two together helps show whether this is a first dengue infection or a repeat one.
Your dengue IgG result is reported as positive or negative, and on its own reflects exposure at any point in the past rather than a specific timeframe. Because IgG can stay detectable for years after any dengue infection, confirming a recent infection needs a second sample roughly two weeks later to check for a rising level. It's rarely ordered completely alone; your doctor usually pairs it with an IgM test so the two results can be read together. A single blood sample is enough for each draw, with no fasting required.
IgG is the antibody your immune system keeps making long after an infection has passed, and with dengue it can remain detectable for years, sometimes for life. This is useful for confirming you've had dengue at some point, but it means a single IgG result can't say whether that exposure happened last month or a decade ago.
Because IgG rises more slowly than IgM in someone's first dengue infection, but can rise fast and strong in someone who's had dengue before, comparing the two together helps doctors work out whether an illness is a first infection or a second one — information that matters because repeat dengue infections carry a higher risk of severe disease. A high IgG relative to IgM, especially early in an illness, points toward a second infection.
To confirm a recent infection using IgG alone, your doctor needs two samples about two weeks apart, looking for a jump from negative to positive or a several-fold rise in level. A single IgG sample taken at just one point in time is better suited to showing past exposure than pinning down when the infection happened.
Not necessarily. IgG can stay detectable for years after any dengue infection, so a single positive result mainly shows past exposure rather than confirming a current illness.
A second sample lets your doctor check whether IgG has gone from negative to positive, or risen sharply, which confirms a genuinely recent infection rather than old exposure.
IgM rises earlier and fades within a few months, marking a recent infection, while IgG builds more slowly but can persist for years, marking exposure at any point in the past.
It can remain detectable for years after a dengue infection, which is why it isn't used alone to time exactly when an infection happened.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
Yes, a positive IgG shows you've been exposed to dengue at some point, even if that infection was years earlier.
Research on dengue antibody patterns has linked secondary infections to a higher risk of complications, including hemorrhagic symptoms and more severe illness, compared with a first infection.
No. No special preparation, including fasting, is needed before this blood draw.