Duke Criteria for Infective Endocarditis (IE)

The Duke criteria are a standardized diagnostic framework for infective endocarditis, originally proposed in 1994 and modified in 2000 (Li et al.). In 2023, they were further updated to the 2023 Duke/ISCVID Criteria (Fowler VG et al., Clin Infect Dis 2023).

Diagnostic Classification

Category	Clinical Criteria
Definite IE	2 major criteria, OR 1 major + 3 minor, OR 5 minor criteria
Possible IE	1 major + 1 minor, OR 3 minor criteria
Rejected	Firm alternate diagnosis; OR resolution with antibiotics ≤4 days; OR no pathologic evidence at surgery on antibiotics ≤4 days; OR criteria for possible IE not met

Pathologic criteria (positive culture/histology from vegetation, abscess, prosthetic valve, or embolus) alone are sufficient for Definite IE.

MAJOR Criteria

A. Microbiologic Criteria (either of the following)

1. Positive blood cultures:

Typical IE organisms (Viridans streptococci, S. gallolyticus [formerly S. bovis], S. aureus, HACEK group, community-acquired enterococci) from 2 separate blood culture sets
Organisms that occasionally/rarely cause IE from 3 or more separate sets
Persistently positive cultures: ≥2 drawn >12 hours apart, or ≥3 of ≥4 drawn with first and last ≥1 hour apart

2. Positive laboratory test (new in 2023):

Positive PCR or nucleic acid-based test from blood for Coxiella burnetii, Bartonella spp., or Tropheryma whipplei
C. burnetii anti-phase I IgG titer >1:800, or isolated from a single blood culture
IgG titer >1:800 for Bartonella henselae or Bartonella quintana by indirect immunofluorescence

B. Imaging Criteria (new in 2023 - expanded beyond echo alone)

1. Echocardiography and/or cardiac CT (any of the following):

Vegetation, valvular/leaflet perforation, aneurysm, abscess, pseudoaneurysm, or intracardiac fistula
Significant new valvular regurgitation (compared with prior imaging)
New partial dehiscence of prosthetic valve

2. ¹⁸F-FDG PET/CT:

Abnormal metabolic activity (at least 3 months after implantation) involving a native or prosthetic valve, ascending aortic graft, intracardiac device leads, or other prosthetic material

C. Surgical Major Criterion (new in 2023)

Evidence of IE observed by direct inspection during cardiac surgery, in the absence of major microbiologic or imaging criteria

MINOR Criteria

A. Predisposing conditions

Previous history of IE
Prosthetic valve or previous valve repair
Congenital heart disease
More than mild valvular regurgitation or stenosis (any etiology)
Endovascular cardiac implantable electronic device (CIED)
Hypertrophic obstructive cardiomyopathy (HOCM)
Injection drug use

B. Fever

Temperature >38°C (100.4°F)

C. Vascular phenomena

Major arterial emboli, septic pulmonary infarcts, cerebral or splenic abscess, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, Janeway lesions, purulent purpura, thromboembolic phenomena

D. Immunologic phenomena

Glomerulonephritis, Osler nodes, Roth spots, positive rheumatoid factor, immune complex-mediated phenomena

E. Microbiologic evidence (falling short of major)

Positive blood cultures for an IE-consistent organism not meeting major criteria
Positive culture/PCR/sequencing from a sterile body site other than cardiac tissue, prosthesis, or embolus

F. Imaging criteria (minor, new in 2023)

Abnormal ¹⁸F-FDG PET/CT within 3 months of prosthetic valve/device implantation (those at >3 months = major criterion)

G. Physical examination (if echocardiography unavailable)

New valvular regurgitation on auscultation (worsening of a pre-existing murmur is not sufficient)

Key Mnemonics & Pearls

Classic peripheral stigmata	Mechanism
Osler nodes	Tender nodules on fingertips/toes - immune complex deposition (minor criterion)
Janeway lesions	Non-tender hemorrhagic macules on palms/soles - septic emboli (vascular, minor criterion)
Roth spots	Retinal hemorrhages with pale center - immune complex (minor criterion)
Splinter hemorrhages	Subungual - vascular emboli (minor criterion)

HACEK organisms (minor causes, need 3+ culture sets): Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella

Key 2023 updates vs. Modified Duke Criteria:

Nuclear imaging (PET/CT) added as major imaging criterion
Molecular diagnostics (PCR, NAT) for fastidious organisms added as major microbiologic criterion
Surgical inspection added as a new major criterion
Predisposition list expanded to include CIED, HOCM, prior IE
Physical exam criterion added for resource-limited settings

Sources: Braunwald's Heart Disease, 11th Ed. (Table 80.3); Textbook of Clinical Echocardiography (Table 14.1 - 2023 Duke/ISCVID Criteria); Fowler VG et al., Clin Infect Dis 2023

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