Can endosonographers evaluate on-site cytologic adequacy? A comparison with cytotechnologists

Background: On-site determination of cytologic adequacy increases the accuracy of EUS-guided FNA (EUS-FNA); however, on-site cytotechnologists are not available to all endosonographers. We hypothesize that experienced endosonographers can accurately assess whether an on-site FNA specimen is adequate. Objective: To determine the accuracy of on-site cytopathology interpretation of EUS-FNA specimens by comparing endosonographers with a cytotechnologist. Design: Prospective double-blind controlled trial. Setting: Academic medical center with a high-volume EUS practice. Patients: Consecutive patients undergoing EUS-FNA of lymph nodes or pancreas tumors. Main Outcome Measurements: Accuracy, sensitivity, and specificity of 3 endosonographers and 1 cytotechnologist for interpretation of cytologic specimen adequacy and diagnosis compared with a criterion standard of a board-certified cytopathologist. Results: There were 59 lymph node, 49 pancreas, and 9 liver specimens (117 total). For determination of adequacy, none of the endosonographers were statistically equivalent to the cytotechnologist (P = .004). For determination of suspicious/malignant versus benign specimens, all 3 endosonographers were inferior (P < .001) to the cytotechnologist. Limitations: This study represents a small group of trained endosonographers in a high-volume practice and may not be applicable to other settings. The sample size does not allow an accurate evaluation of different biopsy sites (eg, pancreas vs lymph node). Conclusions: Even trained endosonographers have variable and, in some cases, inferior abilities to interpret on-site cytologic adequacy compared with cytotechnologists.