A farmer presenting with fever on and off for the past 4 years was diagnosed to be suffering from chronic brucellosis. All of the following serological tests are indicatedl in the diagnosis of chronic brucellosis except:

Patient is suffering from chronic brucellosis. Standard agglutination test identifies mainly the IgM antibodies, which is usually positive in acute infection but may be only weakly positive or even negative in chronic cases. Standard agglutination test is therefore useful in diagnosing acute brucellosis, not chronic brucellosis. Brucellosis is a bacterial zoonosis transmitted directly or indirectly to humans from infected animals, predominantly domesticated ruminants and swine. The disease is known as undulant fever because of its remittent character. Although brucellosis commonly presents as an acute febrile illness, its clinical manifestations vary widely, and definitive signs indicative of the disease is not present. Clinical diagnosis must be suppoed by the results of bacteriologic and/or serologic tests. Ref: Brucellosis in Humans and Animals By Michael J.Corbel, Page 79 ; Harrisosns Principles of Internal Medicine, Chapter 157 ; Brucellosis Research: An Evaluation - A Repo By National Research Council (U.S.), Page 45