<prompt> Diagnosis of tularemia is confirmed using agglutination testing. In the standard tube agglutination test, what should be the single antibody titre for making the test positive?1:400.0972222220.1250.152777778  <response>: A single antibody titer 1:160 is interpreted as a presumptive positive result for diagnosing tularemia. Agglutination test is used to confirm the diagnosis of tularemia. A fourfold increase in titer between paired serum samples collected 2-3 weeks apa is considered diagnostic. Late in infection, titers of 1:20-1:80 may persist for years. Tularemia is caused by F. tularensis, a gram-negative, pleomorphic, nonmotile, non-spore-forming bacillus. Ref: Jacobs R.F., Schutze G.E. 2012. Chapter 158. Tularemia. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo Eds,Harrisons Principles of Internal Medicine, 18e. 