Optimizing tissue acquisition to improve the diagnostic yield of endoscopic ultrasound-guided fine needle biopsy of solid masses: a quality improvement initiative

Background A chart audit (pre-intervention, PRE) of endoscopic ultrasound (EUS)-fine needle biopsy (FNB) of solid masses identified a diagnostic yield of 75%. To improve diagnostic yield, a quality improvement intervention targeting tissue procurement and processing was developed and trialed (post-intervention, POST). Intervention Increase needle passes to ≥3/mass, limit the personnel preparing cytology slides, and replace saline with formalin for cell block preparation. Methods A POST chart audit was undertaken for solid mass EUS-FNB from January 2024-December 2024, with quarterly reviews. Only a definite diagnosis was used to calculate diagnostic yield. ResultsAbout 241 patients underwent 262 EUS-FNBs. Diagnostic yield was 81% in POST vs. 75% in PRE (p = ns). Single passes decreased to 14% in POST vs. 20% in PRE (p = ns), with similar diagnostic yield (57% vs. 56%, respectively). Number of ≥3 passes increased significantly (47% POST vs. 12% PRE, P < .0001). In POST, 86% of single passes were performed in the first half vs. 14% in the second (P = .012). Only 25% of ≥3 passes were performed in the first half vs. 75% in the second (P = .06). Diagnostic yield improved significantly between the first and second halves (72% vs. 90%, P < .0001). Replacing saline with formalin for cell block improved diagnostic yield (57% vs. 75%, P = .062). Limiting the personnel making slides from 25 nurses (PRE) to 3 endoscopists (POST) had no impact on diagnostic yield. Conclusions Critical practice assessment, regular audit, and continued reinforcement led to a significant improvement in EUS-FNB diagnostic yield to 90% by increasing the number of needle passes to ≥3/mass.