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