Infective Endocarditis Diagnosis (Modified Duke) — free guideline decision tool

The modified Duke (and 2023 Duke-ISCVID) criteria classify infective endocarditis as definite, possible, or rejected using major and minor criteria.

Definite = 2 major, or 1 major + 3 minor, or 5 minor; possible = 1 major + 1 minor, or 3 minor; otherwise rejected. Major = typical microbiology or imaging evidence; minor = predisposition, fever, vascular/immunologic phenomena, supporting microbiology.

Use to combine microbiologic, imaging, and clinical findings into a diagnostic category that guides antibiotics and surgical assessment.

A negative transthoracic echo with high clinical suspicion warrants a transesophageal echo before rejecting the diagnosis (original synthesis · not guideline verbatim). The 2023 Duke-ISCVID revision adds cardiac CT, intraoperative findings, and PET/CT and broadens predisposition to CIED/TAVR/prior IE. Pathologic criteria (organism in vegetation/valve tissue) confirm directly and override the clinical count.

For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.

Inputs: Major · microbiology (2 sets of blood cultures with typical IE organisms / persistently positive / single C. burnetii or IgG antibody > 1:800) No, Major · imaging (echo/cardiac CT showing vegetation/abscess/perivalvular involvement/new prosthetic dehiscence; or surgical/PET evidence) No, Minor · predisposition (underlying heart disease/prosthetic valve/CIED/IV drug use/prior IE) No, Minor · fever ≥ 38℃ No, Minor · vascular phenomena (arterial embolism/septic pulmonary infarction/mycotic aneurysm/intracranial hemorrhage/Janeway lesions) No, Minor · immunologic phenomena (glomerulonephritis/Osler nodes/Roth spots/rheumatoid factor) No, Minor · microbiologic evidence (not meeting a major criterion) No → Result: Duke determination Rejected (needs exclusion/reassessment)（Count: Major criteria 0, minor criteria 0 → Rejected (needs exclusion/reassessment), Decision rule: Definite = 2 major or 1 major + 3 minor or 5 minor; possible = 1 major + 1 minor or 3 minor; otherwise rejected, Management direction: Assess other causes of fever/bacteremia; reject if a firm alternative diagnosis exists, or resolution with < 4 days of antibiotics, or no evidence at surgery/autopsy） Inputs: Major · microbiology (2 sets of blood cultures with typical IE organisms / persistently positive / single C. burnetii or IgG antibody > 1:800) Met, Major · imaging (echo/cardiac CT showing vegetation/abscess/perivalvular involvement/new prosthetic dehiscence; or surgical/PET evidence) Met, Minor · predisposition (underlying heart disease/prosthetic valve/CIED/IV drug use/prior IE) Met, Minor · fever ≥ 38℃ Met, Minor · vascular phenomena (arterial embolism/septic pulmonary infarction/mycotic aneurysm/intracranial hemorrhage/Janeway lesions) Met, Minor · immunologic phenomena (glomerulonephritis/Osler nodes/Roth spots/rheumatoid factor) Met, Minor · microbiologic evidence (not meeting a major criterion) Met → Result: Duke determination Definite IE (clinical criteria)（Count: Major criteria 2, minor criteria 5 → Definite IE (clinical criteria), Decision rule: Definite = 2 major or 1 major + 3 minor or 5 minor; possible = 1 major + 1 minor or 3 minor; otherwise rejected, Management direction: Start targeted antibiotics per guidelines (based on blood culture and susceptibility), assess surgical indications (heart failure/uncontrolled infection/high embolic risk/perivalvular abscess), manage with a multidisciplinary IE team）