Duke Classification

The Duke classification for IE is outlined below:

Major criteria

A. Positive blood culture for IE

1. Typical microorganism consistent with IE from two separate blood cultures, as noted below:

• Viridans streptococci, Streptococcus bovis, or HACEK* group, or
• Community-acquired Staphylococcus aureus or enterococci, in the absence of a primary focus

OR

2. Microorganisms consistent with IE from persistently positive blood cultures defined as:

• Two positive cultures of blood samples drawn >12 hours apart, or
• All of three or a majority of four separate cultures of blood (with first and last sample drawn 1 hour apart)

B. Evidence of endocardial involvement

1. Positive echocardiogram for IE defined as:

• Oscillating intracardiac mass on valve (vegetation), or
• Abscess, or
• New partial dehiscence of prosthetic valve

OR

2. New valvular regurgitation (worsening or changing of pre-existing murmur not sufficient)

Minor criteria

• Predisposition: predisposing heart condition or intravenous drug use
• Fever: temperature >38.0 C
• Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial haemorrhage, conjunctival haemorrhages, 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 IE
• Echocardiographic findings: consistent with IE but do not meet a major criterion as noted above

Clinical criteria for IE

Clinical criteria for IE requires:

• Two major criteria, or
• One major and three minor criteria, or
• Five minor criteria