MON-498 Thyroseq V3 GC for Bethesda III and IV: An Institutional Experience

Background: Molecular testing of thyroid nodules classified as indeterminate on fine-needle aspiration (FNA) is used for patient management. ThyroSeq® v3 genomic classifier is a commercially available test that examines a wide spectrum of genomic alterations in a thyroid FNA sample based on algorithmic analysis and reports test results as either negative (including currently negative) or positive. This study reviews our institutional experience with Thyroseq® V3 to distinguish between benign disease versus cancer in thyroid nodules diagnosed as Bethesda III or IV on cytology. Methods: Thyroid nodules with Bethesda III or IV cytology diagnoses and available Thyroseq® V3 results from 12/17 to 8/19 were retrieved from the pathology database. Cytopathology diagnoses were correlated with molecular testing and histopathology. Results: 416 cases (Bethesda III n=252, Bethesda IV n=164) were retrieved: 295 (71%) were reported as Thyroseq® V3 negative and 121 (29%) as positive. The 82.1% (207/252) benign call rate (BCR) of Thyroseq® v3 for Bethesda III was significantly higher (p