BACKGROUND: Controversy remains regarding the effect of needle size on the diagnostic yield of endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration. We conducted a prospective study comparing the diagnostic yield of 19 and 21鈥塆 EBUS needles and hypothesized that the 19鈥塆 have a greater EBUS-guided transbronchial needle aspiration diagnostic yield as compared with the 21鈥塆 needle. METHODS: A total of 60 patients undergoing EBUS-guided transbronchial needle aspiration were enrolled with informed consent. Both 19 and 21鈥塆 needles were used at each lymph node station in alternating fashion, we randomized which needle, to begin with. Two rapid on-site cytology evaluation stations were present and assigned to one of the 2 needles. They reported sample adequacy and prepared a separate cell block per lymph node sampled for their assigned needle. RESULTS: A total of 141 lymph nodes were analyzed. Diagnosis included 69 benign lymph nodes, 47 malignant lymph nodes, 22 noncaseating granulomas, and 3 infected lymph nodes. Five hundred seventy-three passes (average: 4.1 passes/lymph node) were done with 19鈥塆 and 581 passes with 21鈥塆 needles (average: 4.1 passes/lymph node). Diagnostic yield was similar between 19 and 21鈥塆 needles overall (89.4% vs. 88.7%, P=0.71). The 19鈥塆 needles showed higher smear cellularity (32.6% vs. 13.0%, P=0.05), and rapid on-site cytology evaluation adequacy (84.8% vs. 63.0%, P=0.004) in lymph nodes with cancer diagnosis. In 7 of the 141 lymph nodes, samples from only one of the needles provided the final diagnosis. CONCLUSION: There is no difference in the overall diagnostic yield between 19 and 21鈥塆 needles. Further studies are needed to confirm the trend of the superiority of 19鈥塆 in cancerous lymph nodes.
