Published online May 19, 2021 in Vascular Medicine, researchers from the Intersocietal Accreditation Commission (IAC) Vascular Testing division report findings of their multi-centered study of duplex ultrasound for diagnosis of internal carotid artery (ICA) stenosis. The study was developed in response to wide variability in the diagnostic criteria used to classify severity of ICA stenosis across vascular laboratories nationwide and following a survey of members of IAC-accredited facilities supporting efforts toward standardization.