Endobronchial ultrasound-guided transbronchial needle aspirate (EBUS-TBNA): a proposal for on-site adequacy criteria

Abstract

This is a retrospective study of 48 patients who underwent EBUS-TBNA procedure between the periods January 2008 to September 2009 at Long Island Jewish Medical Center. The study was undertaken with the following objectives: First, to define practical and useful on-site adequacy criteria for EBUS-TBNA samples; Second, to understand the diagnostic pitfalls associated with accurate interpretation of EBUS-TBNA samples. EBUS-TBNA procedure was able to diagnose 24/48 (50%) patients with malignancy, 1/48 (2%) suspicious for malignancy, 9/48 (19%) with granulomatous process, and 9/48 (19%) negative for disease. Only five cases (10%) could not be diagnosed with this procedure. Based on our experience, any smear with presence of > 5 low power fields (×100) with ≥ 100 lymphocytes in each and containing < 2 groups of bronchial cells/low power field (×100) can be considered adequate for evaluation. Also, the presence of germinal center fragments renders a smear adequate for evaluation, irrespective of the above mentioned criteria. Adequacy criteria are to be applied only to the smears not showing any identifiable pathology such as malignancy or granuloma. An understanding of diagnostic pitfalls associated with accurate interpretation of EBUS-TBNA samples is essential to avoid false-positive and false-negative diagnosis. To conclude, an effective communication between the clinician and cytologist, an algorithmic approach to diagnosis, and the on-site adequacy criteria proposed in this study can markedly improve the diagnostic yield of the procedure.