This Duke criteria calculator evaluates symptoms for infective endocarditis and allows the clinician to put a quick diagnosis based on patient data. You can find out more about the score criteria and interpretation below the form.

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

How does this Duke criteria for infective endocarditis calculator work?

This is a health tool that helps clinicians diagnose infective endocarditis, a condition that is quite challenging to diagnose. It comprises of 8 criteria divided in major and minor categories. The result obtained in this Duke criteria calculator varies according to the combination of major and minor clinical factors present in the specific case.

The main focus is put on infectious causes, the pathogen agents and the EKG modifications occurring in endocarditis. The minor criteria focuses on the patient temperature without other known cause, predisposing heart conditions, vascular, immunologic and microbiologic phenomena.

The user only needs to tick the boxes with the factors and then the calculator will provide the result, specifying whether there is enough evidence to set the IE diagnosis or not.

Full infective endocarditis diagnosis and prophylaxis

Endocarditis is one of the most complex types of heart infections and is caused by bacteria brought through the bloodstream to the heart. In case there is a predisposition or a trouble with the heart valves or artificial ones have been surgicaly introduced, the bacteria can easily root in the tissue and disrupt the normal body immune responses and facilitate other infections further.

All kind of IE are very serious conditions and if left untreated they damage further the heart valves, lead to disruptions in heart rate and blood flow and can lead to life threatening conditions such as heart failure or stroke.

The Duke criteria study has benefited from further research and a modified version has been presented, one that includes two more pathological diagnosis tools, either histologic or bacteraemia.

The definite histological diagnosis of IE criteria includes intracardiac vegetation, abcess present with active endocarditis. The bacteria diagnosis criteria requires evidence of culture or histology in a vegetation, or in a vegetation that has embolized, or in an intracardiac abscess.

IE can be culture positive or culture negative but the second case usually happens only when prior antibiotics medication has been administered. Some cultures have a rapid growth rate while others have more difficult growth requirements and care should be offered in order not to provide false negative results.

IE is also identified by the type of heart infection, either the right side of the heart, the tricuspid valve is affected or the left side. Also a distinction between native-valve endocarditis and prosthetic-valve endocarditis (early after medical procedure or community acquired) should be made.

Amongst the most common symptoms, fever occurs in 97% of people, followed by general malaise, heart murmur, coughing, sweat, rigor and/or anemia. These can be accompanied by vascular signs such as septic embolism, Janeway lesions, intracranial haemorrhage, splinter haemorrhage or splenic and kidney infarctions. Immunological phenomena determines a blood and albumin transfer to urine.

Clinicians often use the mnemonic FROM JANE to describe the most common clinical symptoms: Fever, Roth's spots, Osler's nodes, Murmur, Janeway lesions, Anemia, Nail haemorrhage and Emboli.

Duke criteria for IE interpretation

Any of the following three scenarios for a definite diagnosis:

■ 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.

A patient who is suspect of endocarditis needs close monitoring, blood cultures, laboratory testing and echocardiography examinations while they are hospitalised. There are two clinical phases, one acute (fulminant condition possibly due to Staphylococcus aureus) and one subacute (due to streptococci of low virulence, progressing slowly over several months) and cases are also rated based on severity and disease progression.

Patients at risk to develop an IE are adults and children with structural heart problems, replacement valves, with previous IE history or people having procedures in the following fields: dental, urinary system, obstetrics gynecology, digestive system, airways - ear, nose, throat or bronchoscopies. These people are advised to go on prophylactic antibiotic regimens before or after the procedure in order to prevent the risk of infection.


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

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

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

27 Aug, 2015