Determinants of single‑pass specimen adequacy in endobronchial ultrasound-guided transbronchial needle aspiration: a real-world study

Background: Although endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) diagnostic yield has been widely studied, factors influencing specimen adequacy from a single puncture remain unclear. This study aimed to identify factors associated with the specimen adequacy of a single EBUS‑TBNA puncture to inform and refine procedural strategies. Methods: This single-center observational study enrolled consecutive patients undergoing EBUS-TBNA. Puncture-level data were collected, and the primary outcome was the single-pass specimen adequacy rate, assessed using the Macroscopic On-site Specimen Evaluation (MOSE) scoring system. Evaluated variables included procedure-related factors (needle pathway, operator experience), lymph-node characteristics (station, size, N stage, presence of computed tomography (CT) hypodense areas), and patient characteristics. A cumulative link mixed model (CLMM) was used to identify independent predictors of specimen adequacy. Results: peripheral), N stage, the presence of a hypodense area, and operator experience were not significant predictors (P>0.05). Multivariate analysis identified lymph node station and a final diagnosis of malignant pathology as independent predictors of specimen adequacy (P<0.05). Conclusions: In this study, specimen adequacy from a single EBUS‑TBNA puncture appeared to be more closely related to malignancy and lymph node station. These findings indicate that disease‑related factors may influence single‑pass yield; however, additional studies are required to validate these results and determine their applicability across different clinical settings.