Appendix B: Duke Criteria for Infective Endocarditis*

Major Criteria†

Blood culture positive for infective endocarditis

Typical microorganisms consistent with infective endocarditis from two separate blood cultures:

Viridans streptococci, Streptococcus bovis, HACEK group, Staphylococcus aureus; or

Community-acquired enterococci, in the absence of a primary focus; or

Microorganisms consistent with infective endocarditis from persistently positive blood cultures, defined as follows:

At least two positive cultures of blood samples drawn >12 hours apart; or

All of three or a majority of four or more separate cultures of blood (with first and last sample drawn at least 1 hour apart)

Single positive blood culture for Coxiella burnetii or antiphase I IgG antibody titer >1:800

Evidence of endocardial involvement

Echocardiogram positive for infective endocarditis (transesophageal echocardiography recommended in patients with prosthetic valves, rated at least "possible infective endocarditis" by clinical criteria, or complicated infective endocarditis [paravalvular abscess]; transthoracic echocardiography as first test in other patients), defined as follows:

Oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative anatomic explanation; or

Abscess; or

New partial dehiscence of prosthetic valve

New valvular regurgitation (worsening or changing of preexisting murmur not sufficient)

Minor Criteria†

Predisposition: predisposing heart condition or injection drug use

Fever: temperature >38°C

Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway lesions

Immunologic phenomena: glomerulonephritis, Osler's nodes, Roth spots, and rheumatoid factor

Microbiological evidence: positive blood culture but does not meet a major criterion as noted above§ or serological evidence of active infection with organism consistent with infective endocarditis

Echocardiographic minor criteria eliminated

* Modifications in bold. (Source: Li JS, Sexton DJ, Mick N, et al. Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis. Clin Infect Dis 2000;30:633–8.)

† Clinical criteria for definite endocarditis requires two major criteria, or one major and three minor criteria, or five minor criteria. Clinical criteria for possible endocarditis requires at least one major criterion and one minor criterion, or three minor criteria.

§ Excludes single positive cultures for coagulase-negative staphylococci and organisms that do not cause endocarditis.