Dengue IgG test is a blood test that measures the levels of immunoglobulin G (IgG) antibodies against the dengue virus. These antibodies are produced by the immune system in response to a dengue infection or vaccination. Dengue IgG test is usually performed along with Dengue IgM test to detect and diagnose a dengue infection. IgG antibodies are typically detected after 1-2 weeks of infection, and remain detectable for months to years. High levels of IgG antibodies indicate a past infection or recent vaccination. However, it should be noted that IgG antibodies cannot distinguish between the four serotypes of the dengue virus, and a secondary infection with a different serotype can lead to severe dengue hemorrhagic fever.