Randomized Trial Comparing Performance of Molecular Markers for Indeterminate Thyroid Nodules

1. All patients undergoing thyroid FNA within the UCLA Health System will be randomized at the time of FNA to a single molecular test (GSC or ThyroSeq v.3). In the previous phase of the study, patients were randomized to the previous versions of a single molecular test (GEC or ThyroSeq v.2). 2. During the FNA, a sample will be collected for the molecular test. 3. If the cytology results are indeterminate (Bethesda categories 3 or 4), the molecular test will be reflexively sent off. 4. We will help patients with indeterminate thyroid nodules to establish care with an endocrinologist, if they do not already have one. The physicians will make treatment recommendations using best practices and incorporating the results of the molecular test. We anticipate that most patients with a positive molecular test will undergo surgery, while the majority with a negative test will be surveiled. 5. Patients who undergo surgery will have histopathologic evaluation of the thyroid, which will determine whether the index thyroid nodule was benign or malignant. 6. Patients who do not undergo surgery will have a followup ultrasound at 6 and 12 months, or sooner at the discretion of the treating physician. 7. We will assess thyroid-specific quality of life at baseline (following initial diagnosis of an indeterminate thyroid nodule) and during followup (at 6 and 12 months) using the short version of Thyroid-Related Patient-Reported Outcome.