8 Confirmed diagnosis A serum specimen that was drawn during the convalescent phase, 4 weeks after the patient was discharged from the hospital, for antibodies to F. tularensis, the titer dilution was 1: 640 (normal titer, <1: 20)8 ConPirmed diagnosis : A serum specimen that was drawn during the convalescent phase, 4 weeks after the patient was discharged from the hospital, for antibodies to F. tularensis; the titer dilution was 1:640 (normal titer, <1:20)