Objective: To determine the diagnostic accuracy of specimens obtained by a surgeon performing office-based ultrasound (US)-guided fine-needle aspiration biopsy (FNAB) of thyroid nodules.
Subjects and methods: From 2003 to 2006, a single surgeon performed 447 consecutive office-based US-guided FNABs without on-site cytological specimen evaluation. Adequate specimens had at least six clusters of follicular cells from at least two separate needle passes.
Results: Non-diagnostic specimens occurred in 16 of 447 (3.6%) nodules, whereas suboptimal specimens occurred in 17 of 447 (3.8%). Adequate samples were obtained in 413 of 447 (92.6%) of specimens. Malignancy was present in 20 of 447 (4.5%) and atypical features were present in 37 of 447 (8.3%). Benign diagnoses were rendered in 357 of 447 (79.9%) of specimens, of which four of 357 (1.1%) represented false-negative results.
Conclusion: Prior publications recommend that obtaining adequate thyroid cytology specimens requires use of US-guided FNAB and on-site evaluation of cytology adequacy. This study demonstrates that a combination of experienced US guidance, both capillary and aspiration sampling, and three to four needle passes produce comparable results while conserving costs and resources.