Dengue IgG/IgM Antibody Rapid Qualitative Test (Fluorescence Immunoassay)

Clinical Significance:

1. Determination of Infection Stage

IgM antibody becomes detectable 3–5 days after fever onset and persists for 30–90 days. A positive IgM result indicates recent or current infection.

IgG antibody appears later. In primary infections, IgG levels rise slowly; in secondary infections, IgG levels are already high early in the illness.

This test allows simultaneous detection of IgM and IgG, helping to differentiate between acute, recent, and past infections.

2. Differentiation Between Primary and Secondary Infection

In endemic regions, most dengue patients experience secondary infections.

Primary infection: IgM positive with low or negative IgG in the acute phase.

Secondary infection: High levels of specific IgG present prior to or simultaneously with IgM response.

Distinguishing primary from secondary infection is clinically important because secondary infection with a heterologous serotype carries a higher risk of severe dengue.

3. Complementary Role in Diagnosis

While NS1 antigen testing is optimal for very early diagnosis (days 1–5), antibody testing becomes valuable after the first few days of illness.

This test is particularly useful for patients presenting later in the disease course when NS1 may no longer be detectable.

4. Utility in Endemic Settings

Due to the high prevalence of secondary infections in endemic areas, the combination of IgM and IgG results helps clinicians quickly assess immune status and make decisions regarding patient monitoring and management.