Modified Duke Criteria for Infective Endocarditis

Diagnostic criteria for infective endocarditis (IE) combining major and minor clinical, microbiologic, and echocardiographic findings to classify definite, possible, or rejected IE.

Major Criterion 1: Positive blood cultures for typical IE organism (S. aureus, viridans streptococci, Enterococcus) from 2 separate samples, OR persistently positive blood cultures (≥2 positive >12h apart, or all of 3 or most of ≥4), OR single positive Coxiella burnetii culture or antiphase I IgG >1:800

Present / Yes

Check if present

Major Criterion 2: Evidence of endocardial involvement (new valvular regurgitation, OR positive echocardiogram showing oscillating intracardiac mass, abscess, new dehiscence of prosthetic valve)

Present / Yes

Check if present

Minor Criterion 1: Predisposition (e.g., injection drug use, prosthetic valve, prior IE)

Present / Yes

Minor Criterion 2: Fever >38°C (100.4°F)

Present / Yes

Minor Criterion 3: Vascular phenomena (arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, Janeway lesions)

Present / Yes

Minor Criterion 4: Immunologic phenomena (glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor positive)

Present / Yes

Minor Criterion 5: Microbiological evidence (positive blood cultures not meeting major criteria, or serologic evidence of active infection with organism consistent with IE)

Present / Yes

Note: Modified Duke criteria are the international standard for IE diagnosis. Culture-negative cases may need extended workup (Coxiella, Bartonella, HACEK, Tropheryma whipplei, fungi).

Modified Duke Criteria Summary

Major Criteria: (1) Positive blood cultures for typical IE organism from 2 separate samples, OR persistently positive cultures; (2) Evidence of endocardial involvement (new regurgitation, oscillating mass, abscess, dehiscence).

Minor Criteria: (1) Predisposition; (2) Fever >38°C; (3) Vascular phenomena; (4) Immunologic phenomena; (5) Microbiological evidence not meeting major.

Classification: Definite = 2 Major OR 1 Major + 3 Minor OR 5 Minor. Possible = 1 Major + 1 Minor OR 3 Minor.

References

Infective Endocarditis - Duke Criteria. Merck Manual Professional Version (2024). https://www.merckmanuals.com/professional/cardiovascular-disorders/endocarditis/infective-endocarditis
Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis. Clinical Infectious Diseases (2000). https://academic.oup.com/cid/article/30/4/633/330171

Medical Disclaimer

This calculator is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.

Clinical judgment is essential; Duke criteria are supportive, not definitive.
Blood culture-negative endocarditis may require serologic or molecular testing.
Echocardiographic findings must be interpreted by experienced operators.

Modified Duke Criteria for Infective Endocarditis

Modified Duke Criteria Summary

References

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