The Brucella antibody IgG test aids in the identification of IgG antibodies against the Brucella abortus bacteria. The brucellosis infection that this bacteria causes travels from animals to people. Your body will produce IgG antibodies to fight off this bacteria if you have brucellosis. After the second week of infection, IgG antibodies are typically found, peaking six to eight weeks later. This examination searches your blood for these antibodies. Individuals with brucellosis experience a wide range of symptoms. While some people may not exhibit any symptoms at all, others may experience major consequences that impact different organ systems.