Dengue IgG Antibody
Dengue IgG antibody develops slowly during primary dengue infection and rises rapidly during a secondary infection with a different serotype. Combined with IgM, it helps distinguish primary from secondary dengue — a crucial clinical distinction because secondary dengue carries higher risk of severe disease. Isolated IgG positivity usually reflects past infection and is common in dengue-endemic regions of India.
Expected Result
Normal
Negative
Positive IgG alone usually reflects past infection. In acute illness, IgM:IgG ratio distinguishes primary from secondary dengue.
This is a qualitative test — results are reported as positive or negative rather than as a numeric range. Interpretation may vary by laboratory method; always review with your doctor.
What a Negative Result Means
A negative dengue IgG in an acute febrile patient (with or without positive IgM) suggests primary dengue — the first infection with any dengue serotype. In a person without current illness, negative IgG simply means no prior dengue infection. In endemic Indian cities, this becomes less common with age.
What a Positive Result Means
A positive IgG with negative IgM in an asymptomatic person reflects past dengue infection at some point — common in endemic areas and not actionable on its own. A positive IgG with positive IgM, especially with IgG rising rapidly or higher than IgM, suggests secondary dengue infection — a higher-risk scenario that warrants close clinical monitoring for severe dengue.
Frequently Asked Questions
Should I get dengue IgG tested if I feel fine?
No. IgG testing alone in a healthy person is not useful. It tells you whether you have had dengue before, but it does not predict future infections or provide clinically actionable information. Dengue IgG only matters when an acute illness is being evaluated.
Why is secondary dengue more dangerous?
Pre-existing antibodies to one dengue serotype can enhance infection by a different serotype (antibody-dependent enhancement), producing more severe disease including dengue hemorrhagic fever and dengue shock syndrome. This is especially relevant in children and young adults with a prior dengue infection — they need closer hospital observation during a second dengue illness.
Does a positive IgG mean I am immune?
Partial and temporary immunity — yes, against the specific serotype you were infected with, for life. But there are four dengue serotypes (DENV-1 to DENV-4), and immunity to one does not protect against the others. In fact, a prior infection raises the risk of severe disease with a different serotype.
Related Infectious tests
See all →ASO Titre (Anti-Streptolysin O)
Antibody against streptococcal toxin — evidence of recent strep infection.
IU/mLInfectiousWidal Test
Antibody test for typhoid fever — used cautiously due to specificity issues.
InfectiousDengue NS1 Antigen
Early dengue virus antigen — detectable in the first week of fever.
InfectiousDengue IgM Antibody
Antibody that rises in the second week of dengue infection.
This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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