Diagnosis involves microbiological cultures from respiratory secretions of patients or serologically with a fourfold or greater increase in antibody titers against C. psittaci in blood samples combined with the probable course of the disease. Typical inclusions called "Leventhal-Cole-Lillie bodies"[5] can be seen within macrophages in BAL (bronchoalveolar lavage) fluid. Culture of C. psittaci is hazardous and should only be carried out in biosafety laboratories.