Optimal timing of repeat thyroid fine-needle aspiration biopsy

The false-negative rate (6.5 %) we found in patients with a benign initial FNA cytology was slightly higher than the rate stated in the guidelines. Additionally, we determined that performing early (<3 months) repeat FNA biopsy for nondiagnostic nodules did not affect the diagnostic yield of subsequent samples. Therefore, we concluded that repeat FNA biopsy should not be delayed longer than 3 months in nondiagnostic nodules with suspicious USG findings and no longer than 6 months in benign nodules with suspicious USG findings. A shorter interval between FNA biopsies will allow for more timely surgical intervention, especially in patients with malignancy in nondiagnostic and benign nodules.