Assessing the Hereditary Hemorrhagic Telangiectasia Algorithms in a Community-Based Patient Population.

Introduction: Hereditary hemorrhagic telangiectasia (HHT) is a rare, genetic, and underdiagnosed disease that causes vascular malformations throughout the body. Two specific combinations of International Classification of Diseases, Ninth Revision-Clinical Modification diagnosis codes, the "HHT Algorithms" (HHTAs), were developed previously from a derivation cohort to help identify undiagnosed HHT cases.

Objectives: To test these 2 algorithms, and a third, newly designed HHTA, in an independent population with available clinical records and thus identify people who might have undiagnosed HHT.