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). Baddour et al Infective Endocarditis in Adults 1437 A diagnosis of IE with the original Duke criteria was based on the presence of either major or minor clinical cri- teria (Tables 2 and 3). The Duke criteria gave diagnostic weight to bacteremia with staphylococci or enterococci only, on the basis of the location of acquisition and with- out an apparent primary focus; these types of bacteremia have the highest risk of being associated with IE.23,25,26 The Duke criteria incorporated echocardiographic find- ings into the diagnostic strategy (Tables 2 and 3; see the Echocardiography section). Six common but less specific findings of IE were included as minor criteria in the original Duke schema (Tables 2 and 3). In the mid to late 1990s, direct analyses of the Duke crite- ria were made in 12 major studies27 38 including nearly 1700 patients composed of geographically and clinically diverse groups (adult, pediatric, and older adult [ 60 years of age] patients; patients from the community; IDU and non-IDU patients; and those with both native and prosthetic valves). The confirmed the high sensitivity and specificity of the Duke criteria and the diagnostic utility of echocardiography in identifying clinically definite cases. Moreover, a retrospective study of 410 patients showed good agreement (72% 90%) between the Duke criteria and clinical assessment by infec- tious disease experts blinded to underlying IE risk factors.39 Table 1. Applying Classification of Recommendations and Level of Evidence A recommendation with Level of Evidence B or C does not imply that the recommendation is weak. 