For certain conditions for which data were either unavailable or inadequate, recommendations were based on expert consensus and clinical experience, and these were ranked as Level of Evidence C. The scheme for the class of recommendations and levels of evidence is summarized in Table 1, which also provides suggested phrases for writing recommendations within each class of recommendation. Diagnosis The diagnosis of IE is straightforward in the minority of patients who present with a consistent history and classic oslerian manifestations: sustained bacteremia or fungemia, evidence of active valvulitis, peripheral emboli, and immu- nological vascular phenomena. In most patients, however, the textbook history and physical examination findings may be few or absent. Cases with limited manifestations of IE may occur early during IE, particularly among patients who are injection drug users (IDUs), in whom IE is often the result of acute S aureus infection of right-sided heart valves. Acute IE may evolve too quickly for the development of immunologi- cal vascular phenomena, which are more characteristic of the later stages of the more insidious subacute form of untreated IE. In addition, valve lesions in right-sided IE usually do not create the peripheral emboli and immunological vascular phe- nomena that can result from left-sided valvular involvement. Right-sided IE, however, can cause septic pulmonary emboli. The variability in clinical presentation of IE and the importance of early accurate diagnosis require a diagnostic strategy that is both sensitive for disease detection and spe- cific for its exclusion across all forms of the disease. In 1994, Durack and colleagues23 from the Duke University Medical Center proposed a diagnostic schema that stratified patients with suspected IE into 3 categories: definite, possible, and rejected cases (Tables 2 and 3). 