Fine needle aspiration (FNA) biopsy is an important and widely accepted method used in the diagnosis of patients with thyroid nodules.The lack of consistency in reporting FNA taken from the thyroid gland has led to divergences in the calculation of the sensitivity and specificity of the method. Discrepancies depend on what was considered to be true or false negative/positive. This resulted in confusion among doctors, who had to decide how to manage the patient with constantly changing positive or negative results of the FNA. The problem was solved in 2007, when "The Bethesda System for Reporting Thyroid Cytopathology" (TBSRTC) was introduced. Generally, TBSRTC, compared to previous systems, results in reducing the number of non-diagnostic/indeterminate cases and enables a better clinical usefulness of the results of the FNA of the thyroid gland. This is probably due to the introduction of more standard criteria for interpreting and reporting. TBSRTC improves communication between cytopathologists, reduces the number of unnecessary operations on benign lesions, and makes it possible to perform the operation on time in patients with malignant lesions and predict the risk of thyroid cancer. It provides a simple and reliable exchange of data not only between various laboratories but also between institutions throughout the world. Research shows that all indicators of malignancy calculated for all categories have similar value to the recommended rate of malignancy.
Keywords: Bethesda System; cytology; fine-needle aspiration; terminology; thyroid.