Performance of Two‐Tiered Subclassification of Atypia of Undetermined Significance in Thyroid Fine‐Needle Aspiration Without Routine Molecular Testing

AUS-Nuclear carries a substantially higher ROM than AUS-Other, with a ROM (54.7%) comparable to the reported positive predictive values of molecular assays such as Afirma GSC (47%, 95% CI: 36%-58%) and ThyroSeq v3 (66%, 95% CI: 56%-75%). These findings support the clinical utility of the two-tiered AUS subclassification in enhancing risk stratification, particularly in settings where molecular testing is not routinely available.