The Frequency of ‘Atypia of Undetermined Significance’ Interpretations for Thyroid Fine-Needle Aspirations Is Negatively Correlated with Histologically Proven Malignant Outcomes

Individual cytopathologist AUS rates were variable and often exceeded the recommended target of 7%. The application of recently published defined diagnostic criteria, along with directed cytopathologist feedback, may reduce observer variability and appropriately lower AUS utilization.