DENGUE (IGM & IGG)
Dengue IgM and IgG antibodies can be used to determine if someone has been infected with the dengue virus, and to differentiate between primary and secondary infections:
IgM antibodies
These antibodies are produced early in an infection, and can be detected 3–7 days after exposure. A positive IgM test indicates a recent infection, but it can also be caused by a cross-reaction with a similar virus like chikungunya. IgM antibodies can remain detectable for up to 6 months after the infection has resolved.
IgG antibodies
These antibodies are produced 7–14 days after infection, and can be detected for months or even years. A positive IgG test indicates exposure to the virus in the past.
IgM/IgG ratio
The ratio of IgM to IgG antibodies can be used to distinguish between primary and secondary infections. A primary infection is indicated by an IgM/IgG ratio greater than 1.2, while a secondary infection is indicated by a ratio less than 1.2.
Test results
A negative test for both IgM and IgG antibodies may indicate that the person doesn't have a dengue infection, or that the antibody levels are too low to detect.
