• Diagnosis
  • Background
  • Pediatrics
  • Lab Tests
  • References
  • Related Content

Indications for Testing

  • Risk factors and appropriate clinical presentation

Criteria for Diagnosis

Laboratory Testing

  • CBC – frequently leukocytosis and left shift toward immature cell forms
  • Blood cultures – 3 sets from separate venipuncture sites; first and last set at least 1 hour apart
    • Perform prior to antibiotic administration
  • C- reactive Protein (CRP)
  • For blood culture-negative disease, consider
  • Urine analysis – may demonstrate hematuria, proteinuria, pyuria in many patients

Imaging Studies

  • Transthoracic echocardiogram (TTE) or transesophageal echocardiogram (TEE) is the gold standard for visualization of vegetations, but negative study does not rule out endocarditis
    • TTE
      • Recommended first test
      • Sensitivity dependent on vegetation size – if >10 mm, test is 100% sensitive
    • TEE
      •  Use in patients with high clinical suspicion and negative TTE
      •  Very sensitive – negative study has negative predictive value of 90%

Differential Diagnosis

Endocarditis is an infection of the endocardium usually associated with infection of the cardiac valve leaflets.


  • Incidence – 3-4/100,000; incidence increases with age (up to 20/100,000)
  • Age – mean 30-60 years, depending on population
  • Sex – M>F, 3:1 to 9:1


  • Variety of organisms – Staphylococcus and Streptococcus spp account for most cases
  • Specific medical conditions
    • Intravenous drug use (IVDU) – Staphylococcus spp, Streptococcus aginosus group
    • Rheumatic heart disease – Streptococcus aginosus group
    • Elderly with gastrointestinal neoplasms – Streptococcus bovis
    • Health care associated infection – Enterococcus spp, Staphylococcus spp
    • Prosthetic valves – Staphylococcus spp
    • Culture negative disease – CoxiellaBartonella, BrucellaHACEK organisms (Haemophilus spp, Aggregatibacter spp [A. aphrophilusA. actinomycetemcomitans], Cardiobacterium hominisEikenella corrodensKingella kingae)
    • Fungi – yeastsmolds
      • Usually 2-3 months after LVAD implantation (not initally)

Risk Factors

  • IVDU
  • Structural heart disease – rheumatic carditis, valvular stenosis, congenital heart disease, prosthetic heart valves
  • Hemodialysis
  • Cardiovascular prostheses, intravascular devices
  • Poor dentition
  • Human immunodeficiency virus (HIV)
  • Prior episode of infective endocarditis
  • ​Age >60 years


  • Classification – native valve endocarditis, prosthetic valve endocarditis, and nonvalvular device endocarditis (eg, pacemaker, LVAD), right- versus left-sided valves
  • Turbulent blood flow produced by abnormalities on valvular leaflets
    • In patients with rheumatic heart disease, mitral valve most commonly involved; aortic valve second most commonly involved
    • Right-sided endocarditis more common with IVDU
  • Transient bacteremia occurs
    • Bacteria naturally adhere to abnormal tissue and form vegetations on the valve
    • Bacteria proliferate within the vegetations

Clinical Presentation

  • Constitutional – fever, anorexia, night sweats, weight loss
    • Patients with cardiac-device related IE may only have these symptoms normally
  • Cardiovascular – new onset murmur, congestive heart failure, dysfunctional prosthetic valve
  • Renal – glomerulonephritis
  • Embolic phenomena
  • Osler nodes – painful blue or purple nodules on the fingers, toes, palms, and soles
  • Roth spots – retinal hemorrhages with central white spots
  • Janeway lesions – nontender nodules on hands and feet
  • Splinter hemorrhages – subungual linear hemorrhages on the long axis of the distal third of nail
  • Complications
    • Valvular collapse with heart failure
    • Periannular extension of the infection into the adjacent myocardium
    • Rupture of the myocardium from extension
    • Embolization – highest with left-sided lesions
      • Stroke
    • Mycotic aneurysm
    • Splenic/hepatic abscesses
    • Intracardiac abscesses


Clinical Background


  • Incidence – lower than in adult population

Risk Factors


  • Streptococcus aginosus group – rheumatic heart disease
  • Staphylococcus epidermidis – nosocomial infection

Clinical Presentation

  • Constitutional – lethargy, fever, malaise
  • Cardiovascular – new onset murmur
  • Adult manifestations such as Osler nodes and Janeway lesions uncommon
  • Complications


  • Refer to Diagnosis tab

Indications for Laboratory Testing

Tests generally appear in the order most useful for common clinical situations.
Click on number for test-specific information in the ARUP Laboratory Test Directory

CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification


Testing is limited to the University of Utah Health Sciences Center only

C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Additional Tests Available

Sedimentation Rate, Westergren (ESR) 0040325
Method: Visual Identification


Marker of inflammation

Organism Identification by 16S rDNA Sequencing 0060720
Method: 16S rDNA Sequencing

Coxiella burnetii (Q-Fever) Antibodies, IgG and IgM, Phase I and II with Reflex to Titer 2012634
Method: Semi-Quantitative Indirect Fluorescent Antibody


Confirm infectious agent as C. burnetii (Q-fever) in symptomatic patients

Reflex – for IgG or IgM testing, if any Phase I or Phase II screening result is Indeterminate or Positive, then titer(s) will be added

Bartonella Species by PCR 0093057
Method: Qualitative Polymerase Chain Reaction

Rheumatoid Arthritis Panel 2003277
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Immunoturbidimetry

Anti-Nuclear Antibodies (ANA), IgG by ELISA with Reflex to ANA, IgG by IFA 0050080
Method: Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody


American Society for Clinical Pathology. Choosing Wisely - Five Things Physicians and Patients Should Question. An initiative of the ABIM Foundation. [Last revision Feb 2015; Accessed: Jan 2016]

Baddour L, Wilson W, Bayer A, Fowler V, Bolger A, Levison M, Ferrieri P, Gerber M, Tani L, Gewitz M, Tong D, Steckelberg J, Baltimore R, Shulman S, Burns J, Falace D, Newburger J, Pallasch T, Takahashi M, Taubert K, Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association, Infectious Diseases Society of America. Infective endocarditis: diagnosis, antimicrobial therapy, and management of complications: a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, Circulation. 2005; 111(23): e394-434. PubMed

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

Wilson W, Taubert K, Gewitz M, Lockhart P, Baddour L, Levison M, Bolger A, Cabell C, Takahashi M, Baltimore R, Newburger J, Strom B, Tani L, Gerber M, Bonow R, Pallasch T, Shulman S, Rowley A, Burns J, Ferrieri P, Gardner T, Goff D, Durack D, American Heart Association. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Cou J Am Dent Assoc. 2008; 139 Suppl: 3S-24S. PubMed

General References

Calabrese F, Carturan E, Thiene G. Cardiac infections: focus on molecular diagnosis. Cardiovasc Pathol. 2010; 19(3): 171-82. PubMed

Duke Criteria for Infective Endocarditis (IE). MedicalCRITERIA.com. [Last updated Aug 2014; Accessed: Jan 2016]

McDonald J. Acute infective endocarditis. Infect Dis Clin North Am. 2009; 23(3): 643-64. PubMed

Nataloni M, Pergolini M, Rescigno G, Mocchegiani R. Prosthetic valve endocarditis. J Cardiovasc Med (Hagerstown). 2010; 11(12): 869-83. PubMed

Pierce D, Calkins B, Thornton K. Infectious endocarditis: diagnosis and treatment. Am Fam Physician. 2012; 85(10): 981-6. PubMed

Que Y, Moreillon P. Infective endocarditis. Nat Rev Cardiol. 2011; 8(6): 322-36. PubMed

Silverman M, Upshaw C. Extracardiac manifestations of infective endocarditis and their historical descriptions. Am J Cardiol. 2007; 100(12): 1802-7. PubMed

Thanavaro K, Nixon J. Endocarditis 2014: an update. Heart Lung. 2014; 43(4): 334-7. PubMed

Thuny F, Grisoli D, Collart F, Habib G, Raoult D. Management of infective endocarditis: challenges and perspectives. Lancet. 2012; 379(9819): 965-75. PubMed

Medical Reviewers

Last Update: February 2016