Background: The immediate assistance of a cytologist during EUS-guided FNA is not universal. The optimal number of fine needle passes during EUS-guided FNA has not been determined in a prospective study. The aim of this study was to determine the optimal number of passes required to obtain a correct diagnosis.
Methods: Seven or more passes were made with a fine needle into a variety of lesions during EUS-guided FNA. Adequacy of the aspirate, diagnosis, and a "certainty score" were recorded after each pass and interpreted sequentially by a cytopathologist. Surgical histopathology and 1-year clinical follow-up were used as reference standards. The percentage of correctly diagnosed cases was calculated and stratified according to organ, disease group, and EUS characteristics of the lesion.
Results: Lesions from 95 patients were categorized into the following locations: pancreas, lymph node, and miscellaneous. The sensitivity and specificity for 7 passes from the pancreas and miscellaneous lesion groups were, respectively, 83% and 100%. The sensitivity and specificity for 5 passes from the lymph node group were, respectively, 77% and 100%.
Conclusions: During EUS-guided FNA, at least 7 passes with a fine needle into pancreatic and miscellaneous lesions, and 5 passes into lymph nodes are needed to ensure a high degree of certainty for making a correct diagnosis.