Diagnosis of fungal IE is limited by lower sensitivity of blood cultures for yeast and virtually no sensitivity for filamentous fungi. Right-sided endocarditis, in which organisms are fil- tered by the lungs, and marantic endocarditis (a noninfectious condition and a synonym for NBTE) are also more difficult to confirm by blood culture. Other less common organisms such as Bartonella spe- cies, Tropheryma whipplei, Coxiella burnetii (Q fever), and Brucella species may cause CNE. Legionella pneumophila and Mycoplasma species occasionally cause CNE, but the role of Chlamydia (now Chlamydophila) species remains Although there is less emphasis on requesting extended incubation of cultures than there was in the past, positive results may be missed unless blood cultures are held for extended ( 14 days) incubation and, in some cases, spe- cial culture methodologies that are not performed routinely are included. At times, the microbiological diagnosis can only be made by molecular confirmation of material removed at the time of surgery, including vegetations, thrombi, emboli, or valves. Frequently, patients have recently received or are cur- rently receiving antibiotic therapy. In those patients who have received <4 days of antibiotic drugs, cessation of treatment can be useful in providing a culture diagnosis after a few days. Consultation with an infectious diseases expert and with all care providers can be beneficial in making such a decision. Rates of cardiovascular surgery in the management of patients with IE have been increasing, and this may offer secondary benefits in providing material for diagnosis. Members of the writing committee stressed the impor- tance of consultation with the microbiology laboratory in all cases of CNE to optimize the chance of identification of the causative microorganism. 