LAUSR

In the past decades, fine-needle aspiration cytology (FNAC) was the primary option for the diagnosis of suspicious lymph nodes on ultrasound in differentiated thyroid cancers (DTC). However, false-negative (6–18%) and nondiagnostic (up to 20%) results are common, resulting in high rates of misdiagnosis. To improve the diagnostic performance of FNAC, measurement of thyroglobulin (Tg) concentration in the washout fluid of the needle used in FNAC (FNA-Tg) was introduced by Pacini et al. in 1992. FNA-Tg was proved to have high accuracy for detection of nodal metastases from DTC, especially in patients previously treated by thyroidectomy. However, due to the lack of standardization of the sample preparing and assessing procedures, the cutoff value for diagnosis is still under debate. Moreover, the influence of serum Tg and thyroidectomy status on the performance of FNA-Tg is unclear.