Febrile Antigens are used in agglutination tests as an aid in the diagnosis of certain febrile diseases such as salmonellosis, brucellosis, and rickettsial diseases. The patient's serum is tested directly for monologous antibodies by either a slide or tube agglutination test. These tests are qualitative and semi-quantitative. The rapid slide test is used primarily as a screening procedure and is especially useful when large numbers of sera must be examined. The tube test should be used to confirm positive results obtained by the slide test. Febrile Control Antisera are used in agglutination tests in conjunction with Febrile Antigens as positive or negative controls. Each set contains ten antigens and five controls, packaged in dropper vials in a special plastic tray. Antigens and controls are also packaged individually.