Infective Endocarditis Duke Criteria

Evaluates patient symptoms to help with infective endocarditis diagnosis.

In the text below the calculator there is more information on the criteria used and on diagnosing or ruling out IE.

The Duke criteria consists of 8 criteria (2 major and 6 minor) which evaluates most common patient signs and symptoms to help with diagnosis of infective endocarditis.

The focus is put on infectious causes, the possible pathogen agents and on the presence of EKG modifications.

Infective endocarditis diagnosis is deemed definite if there are:

■ 2 major criteria and no or more minor criteria;

■ 1 major criteria and 3 or more minor criteria;

■ 0 major criteria and 5 or 6 minor criteria.

IE diagnosis is possible when:

■ 1 major criterion and 1 minor criterion are present;

■ 3 minor criteria are present.


Major Diagnostic Criteria

- Positive from 2 separate cultures with evidence of viridans streptococci, Staphylococcus aureus, Streptococcus bovis or something from the HACEK group (Haemophilus spp. Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella spp., and Kingella kingae).

- Evidence of community-acquired Staphylococcus aureus or enterococci in absence of a primary focus.

- Persistently positive culture with recovered microorganisms after 12 hours.

- Persistently positive cultures with recovered microorganisms from all 3 or a majority of 4 separate cultures of blood drawn with at least one hour difference in between.

- Single positive blood culture for Coxiella burnetti or phase I antibody titer >1:800.

- Oscillating intracardiac mass on valve or supporting structures in the path of regurgitant jets, or on implanted material in the absence of an alternative anatomic explanation.

- Abcess.

- New partial dehiscence of prosthetic valve.

- New valvular regurgitation by changing/ worsening a pre-existing murmur.


Minor diagnostic criteria

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The criteria explained

This model provides major and minor criteria which help with the diagnosis of infective endocarditis based on patient symptoms, possible infection causes and pathogen agents and the EKG modifications.

The criteria used is summarized in the table below:

Duke Criteria Description
Major Positive blood culture for IE: from 2 separate cultures, evidence of community acquired Staphylococcus aureus, persistent positive culture etc.
Evidence of endocardial involvement - echocardiogram showing oscillating intracardiac mass on valve or supporting structures in the path of regurgitant jets etc.
Minor Predisposing heart conditions or IV drug use
Temperature above 100.4° F (38° C)
Vascular phenomena
Immunologic phenomena of either glomerulonephritis, Osler nodes or Roth spots
Microbiological evidence not meeting the major criteria or serological test
Electrocardiographic findings less significant than those from major criteria

The Duke criteria study has benefited from further research and a modified version has been presented.


Result interpretation

According to the original study, there are three types of results. The criteria are deemed as definite IE diagnosis in either of the following three scenarios:

■ 2 major criteria and no or more minor criteria;

■ 1 major criteria and 3 or more minor criteria;

■ 0 major criteria and 5 or 6 minor criteria.

The criteria indicate possible infective endocarditis diagnosis when:

■ 1 major criterion and 1 minor criterion are present;

■ 3 minor criteria are present.

When infective endocarditis is suspected, the patient needs to undergo laboratory testing and echocardiographic examinations.


About the study

The criteria have been designed in 1994 following a study by Durack et al. Retrospective data from a cohort of 353 patients (405 consecutive cases of suspected IE) was analysed based on two major criteria (typical blood culture and positive echocardiogram) and on six minor criteria (predisposition, fever, vascular phenomena, immunologic phenomena, suggestive echocardiogram and suggestive microbiologic findings).

The study also defined three diagnostic categories:

■ Definite diagnosis by pathologic or clinical criteria;

■ Possible diagnosis;

■ Rejected diagnosis.

55 of the 69 pathologically confirmed cases were classified as clinically definite endocarditis by the Duke Criteria (compared to only 35 by older criteria).

The application of the new criteria increases the number of definite diagnoses and helps with more accurate and rapid diagnosis of patients with suspected endocarditis.

The criteria can also be employed as entry criteria for epidemiologic studies and clinical trials.


Infective endocarditis diagnosis

Endocarditis is a bacterial heart infection, most often in patients with a predisposition or an issue with the heart valves or artificial ones that have been surgically introduced. The bacteria install in the cardiovascular tissue and disrupts the normal immune response.

If left untreated IE can lead to further damage to heart valves, impaired blood flow and even develop into life threatening conditions such as heart failure or stroke.

Fever is one of the most common symptoms of this infection (occurring in 97% of cases). Other symptoms are described in the table below:

heart murmur general malaise kidney infarctions
anemia Janeway lesions splinter haemorrhage
joint pain intracranial haemorrhage splenic infarctions
coughing sweat septic embolism

Common diagnosis takes place after positive culture but in some cases, false negatives may occur because of previous antibiotic medication. Some cultures have a rapid growth rate while others have more difficult growth requirements.

There are two clinical phases of the disease:

■ An acute phase: fulminant condition possibly due to Staphylococcus aureus;

■ A subacute phase: caused by streptococci of low virulence, progressing slowly over several months.

IE is also identified by the type of heart infection and whether it is present on the right or left side of the heart. A distinction is made between native-valve endocarditis and prosthetic-valve endocarditis.

The categories of patients that are at risk of IE, and might require prophylactic antibiotic regimens before or after surgical procedures, include adults and children with:

■ Structural heart problems;

■ Replacement valves;

■ Previous IE history;

■ Who undergo certain medical procedures: dental, urinary system, obstetrics gynecology, digestive system, airways - ear, nose, throat or bronchoscopies.


Original source

Durack DT, Lukes AS, Bright DK. New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service. Am J Med. 1994 Mar;96(3):200-9.

Other references

1. Li JS, Sexton DJ, Mick N, Nettles R, Fowler VG Jr, Ryan T, Bashore T, Corey GR. Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis. Clin Infect Dis. 2000; 30(4):633-8.

2. Pérez-Vázquez A, Fariñas MC, García-Palomo JD, Bernal JM, Revuelta JM, González-Macías J. Evaluation of the Duke criteria in 93 episodes of prosthetic valve endocarditis: could sensitivity be improved? Arch Intern Med. 2000; 160(8):1185-91.

Specialty: Cardiology

System: Cardiovascular

Objective: Diagnosis

Type: Criteria

No. Of Criteria: 8

Year Of Study: 1994

Article By: Denise Nedea

Published On: June 8, 2017

Last Checked: June 8, 2017

Next Review: June 8, 2023