Retrospective evaluation of instituted standard adequacy criteria for on-site adequacy assessment of thyroid fine-needle aspiration.

This retrospective study was conducted to investigate the impact of using instituted standard criteria for on-site assessment of specimen adequacy on fine-needle aspiration (FNA) diagnosis of thyroid nodules. The study included a total of 1,031 thyroid FNAs that were performed and assisted with on-site adequacy assessment using instituted standard criteria from July 2006 to March 2009. Adequate specimens require the presence of at least six groups of follicular cells in total on Diff-Quik stained smears with a minimum of 10 cells in each group. Agreement on specimen adequacy between on-site and final assessment, nondiagnostic rate, distribution of cytologic diagnoses, and cytohistologic concordance for cases with surgical follow-up was evaluated. Implementing the instituted standard criteria resulted in 93% level of agreement on specimen adequacy between on-site and final assessment. Nondiagnostic rate upon final assessment was 10.7%. Cytohistologic concordant rate reached 93.9% and 82.3% for nonneoplastic and neoplastic lesions, respectively. Most importantly, this approach to standardization not only provided diagnostic consistency among cytopathologists, but also minimized confusions and enhanced effective communication. Thus, high satisfactions have been achieved from endocrinologists/radiologists who utilized our on-site assessment service and/or participated in the management of thyroid nodules.