Diagnostic criteria for infective endocarditis (Li 2000).

What it is and when to use it

The Modified Duke Criteria classify the probability of infective endocarditis by combining microbiological data (blood cultures), imaging (echocardiography and, in the updated versions, also CT, PET/CT and MRI) and clinical findings. They are organized into major and minor criteria and are used when endocarditis is suspected on native valves, prosthetic valves or cardiac devices. They are the diagnostic criteria recommended by the ESC 2023 guideline on infective endocarditis (ESC 2023/Duke-ISCVID 2023 criteria), an update of the classic 2000 Modified Duke Criteria.

How to interpret it

The diagnosis is classified into three categories. Definite endocarditis: 2 major criteria, or 1 major + 3 minor, or 5 minor criteria (or pathological/microbiological confirmation from valve tissue or a vegetation). Possible endocarditis: 1 major + 1 minor, or 3 minor criteria. Rejected endocarditis: a firm alternative diagnosis, resolution with 4 days or fewer of antibiotics, or criteria for possible endocarditis are not met. A classification of possible does not rule out disease and mandates reassessment with further testing.

Limitations and when not to use it

Validated in patients with clinical suspicion of infective endocarditis; performance is lower in prosthetic valve endocarditis, intracardiac devices and culture-negative cases, where advanced imaging and serologies are needed. They are a diagnostic classification tool, not a population screening test, and do not estimate mortality risk, surgical indication or treatment duration. No rule replaces clinical judgement or assessment by a multidisciplinary endocarditis team.

Frequently asked questions

What is the difference between definite and possible endocarditis on the Duke criteria?

Definite requires 2 major criteria, 1 major plus 3 minor, or 5 minor (or histological proof); possible requires 1 major plus 1 minor, or 3 minor. Possible signals persistent suspicion that warrants further investigation.

Do the Modified Duke Criteria include PET-CT?

Yes; the ESC 2023/Duke-ISCVID update adds abnormal ¹⁸F-FDG PET/CT uptake on a prosthetic valve or material as a major imaging criterion, alongside cardiac CT.

Can endocarditis be diagnosed with negative blood cultures?

Yes; in culture-negative endocarditis the diagnosis relies on serology (for example Coxiella burnetii), PCR and imaging, but the sensitivity of the criteria falls and cases often remain in the possible category.