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Genetic and Rare Diseases Information Center (GARD)

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Long QT syndrome


* Not a rare disease
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Tests & Diagnosis

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How is long QT syndrome diagnosed?

Long QT syndrome is diagnosed on the basis of electrocardiographic (EKG) findings, clinical findings such as congenital deafness or unexplained fainting, and family history of long QT syndrome or sudden cardiac death. Genetic testing is often performed in families in whom the diagnosis of long QT syndrome has been made or is suspected on clinical grounds.
Last updated: 10/4/2013


  • Orphanet lists international laboratories offering diagnostic testing for this condition. Click here and scroll down the page to learn more about the processes of certification, accreditation, and external quality assessment available to these labs. Click on Orphanet to view the list.