Factors Influencing Somatic Genetic Testing for Vascular Anomalies at Two Academic Centers

• Genetic testing is an important tool in the management of vascular anomalies, but not all patients receive it. • Higher odds of prior authorization associated with skin findings, male sex. Lower odds with higher ADI at 1 center. Vascular anomalies (VAs) are rare disorders with abnormal development of blood and lymphatic vasculature, and surrounding tissues. Understanding the genetic etiology of VAs guides treatment with targeted inhibitors. This study compares patterns and outcomes of genetic testing in VA populations at two centers. Of 421 patients (mean age 10 years, 55.6% female), 61.7% underwent prior authorization (PA) for genetic testing, 84% had testing approved, 93% completed testing. Seventy percent of completed tests had pathogenic or likely pathogenic results. A positive result was not associated with sample type (skin biopsy vs. surgical pathology; fresh vs. archived). A greater odds of initiating PA was associated with presence of skin findings, male sex. A lower odds was associated with higher area deprivation index at one center. This study highlights that genetic testing effectively finds causative variants, but not all patients can complete it, and advocates for increased access to genetic testing.