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Comparison of Sample Adequacy and Diagnostic Yield of the 21-G and 25-G EBUS TBNA Needles.

BACKGROUND
Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS TBNA) of mediastinal lymphadenopathy has been shown to be equivalent and possibly even superior to mediastinoscopy. Since the original dedicated 22-G aspiration needle, 21-G, 25-G, and recently 19-G needles have been introduced. Smaller needles may be more flexible and adept at accessing more difficult nodes, and may have less blood contamination compared with larger needles.


PATIENTS AND METHODS
This is a prospective observational study of 50 consecutive patients who underwent endobronchial ultrasound-guided transbronchial needle aspiration with a 21-G needle and a 25-G needle for a total of 100 biopsies. The study slides were examined by a dedicated lung cytopathologist, who was blinded to the needle size used for each slide. Demographic data, and lymph node size were recorded. Comparisons between the 2 needles with regards to sample adequacy and diagnostic yield was performed using the McNemar test for dichotomous variables and marginal homogeneity test for nondichotomous variables since samples were related.


RESULTS
The majority of lymph nodes (96%) were at least >1 cm. Adequate specimens were obtained in 78% of cases with the 21-G needle and 86% of cases with 25-G needle (P-value=0.424). The overall diagnostic yield was 74% and 80% with the 21-G needle and 25-G needle, respectively (P-value=0.607).


CONCLUSION
Our study demonstrates that the there is no difference in terms of specimen adequacy and diagnostic yield when the 25-G needle is compared with the 21-G needle.