Although the etiologies of sudden cardiac death (SCD) are diverse, genetic mutations associated with cardiomyopathic and channelopathic diseases are major causes, and clinically available genetic tests offer the potential to identify at-risk family members, contribute to risk stratification, and guide therapeutic intervention. Recently, the first large-scale systematic studies exploring the background genetic "noise" rate of these tests have been conducted and offer guidance in interpreting positive genetic test results.