Brucella Antibody, IgG, EIA

Brucella Antibody, IgG, EIA is a qualitative serologic test used to identify human IgG antibodies directed against Brucella spp., aiding the diagnosis of brucellosis (undulant fever/Malta fever) when interpreted with symptoms, exposure history, and complementary laboratory data. The assay is applicable across acute, subacute, and chronic presentations of disease and can be used to monitor treatment by tracking changes in antibody levels over time. In brucellosis serology, IgG detection contributes to assessing active infection or prior exposure, and evaluation is strengthened by paired specimens or additional serologic methods performed in parallel.

Brucellosis is a zoonosis caused by Brucella spp., small gram-negative coccobacilli that are invasive and capable of intracellular persistence. In humans, B. melitensis is most frequently implicated, followed by B. abortus, B. suis, B. canis, and marine species. Infection is typically acquired through ingestion of unpasteurized dairy products or undercooked meat, as well as occupational or laboratory exposure; person-to-person transmission is rare but has been documented, including via breast milk. Clinical manifestations range from an acute or subacute febrile illness with lymphadenopathy and hepatosplenomegaly to chronic or localized disease involving the musculoskeletal, neurologic, cardiovascular, or genitourinary systems. Serologic diagnosis depends on detecting antibodies to Brucella antigens: IgM usually becomes detectable around days 6–7, while IgG predominates by approximately week 2. Rising antibody titers over a four-week interval support recent infection, and a fourfold increase between paired sera is considered diagnostically significant. Persistent elevation of titers may reflect ongoing infection, whereas declining titers can indicate effective therapy. Results are interpreted alongside clinical data and other laboratory findings; nucleic acid amplification testing may be used as a complementary approach.