Waste not, want not: diagnostic material found in suction syringe aspirate during endobronchial ultrasound guided transbronchial needle aspiration.

Background: Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is a frequently performed procedure. Suction is utilized during this procedure and may occasionally result in the collection of aspirated material, the diagnostic utility of which is uncertain. This study aims to determine the contents of the suction syringe aspirate and its diagnostic value.

Methods: The suction syringe aspirate was pooled in a container and sent for analysis. We retrospectively reviewed the cytological outcomes of these specimens in comparison to the diagnosis determined by EBUS-TBNA between 2015-2018. The primary outcome was the percent agreement between the diagnostic material found in the suction syringe aspirate, and the final diagnosis established by EBUS-TBNA.

Results: Forty-four patients were included. Percent agreement was calculated as the percent in which the suction syringe aspirate diagnosis agreed with the EBUS-TBNA diagnosis. The percent agreement of any diagnosis was 90.9% (95% CI: 78.7-97.2%). Two of the 44 diagnoses (4.5%) were established based solely on the suction syringe aspirate, both cases of granulomatous inflammation.

Conclusions: Our results suggest that material collected in the suction syringe has a very high percent agreement with the final diagnosis established by EBUS-TBNA. Furthermore, the suction syringe aspirate may represent the sole diagnostic material in nearly 5% of cases. Given the additional diagnostic material in the suction syringe aspirate, it is reasonable to pool the aspirate with the primary specimen in an effort to enrich the overall diagnostic specimen. This practice may improve the likelihood that the specimen will be sufficient for additional molecular analysis, although further study is necessary. Care must be taken when more than one needle is involved to ensure that a new suction syringe is also used to avoid inadvertent upstaging by specimen contamination.