Optimizing Diagnostic Accuracy of Fine Needle Aspiration Biopsy Calcitonin Measurements in Detecting Medullary Thyroid Carcinoma.

The optimal cutoff value of calcitonin (Ctn) levels measured using an electrochemiluminescence immunoassay (ECLIA) obtained from the washout fluid of fine needle aspiration (FNA-Ctn) for the diagnosis of medullary thyroid carcinoma (MTC) is currently not established. We evaluated the diagnostic accuracy and clinical utility of FNA-Ctn for the diagnosis and location of MTC in patients with nodular or multinodular goiters. This was a case-control study nested on a prospective multicenter cohort of patients with nodular or multinodular goiter, normal or elevated serum Ctn, and thyroidectomy indications.