Is the rate of frozen section discordance affected by subspecialty sign out? A quality improvement study

Background: Monitoring frozen section (FS) and final permanent section (PS) correlation is a valuable quality assurance metric in surgical pathology. The discordant FSs, at our institution, are categorized as minor if there is little or no perceived or actual clinical significance and major if there is major or potentially major clinical significance, which is determined by the final sign out pathologist. We sought to determine if the subspecialty sign out (SSSO) model, which was instituted in July of 2015, has adversely impacted our discordance rate. Methods: We retrospectively reviewed the discordance rates (DRs) before (January 2012-June 2015) and after (July 2015-2017) SSSO. The monthly intraoperative consultation FS and PS correlation data were analyzed from January 2012 to January 2018. The DRs were compared for minor, major and combined disagreements (minor + major) before and after SSSO. Results: There were 7,045 total frozen sections with 2,989 after SSSO and 4,056 prior to SSSO, of which 139 had minor disagreements (74 prior to SSSO and 65 after SSSO) and 42 had major disagreements (26 prior to SSSO and 16 after SSSO). The average combined DRs per month; pre and post SSSO were 2.17 and 3.0, respectively. The difference was statistically significant for the minor (p=0.005), not statistically significant for the major (p=1) and statistically significant for the combined (p=0.014) disagreements. Conclusion: Our data shows that SSSO appears to increase FS discordance rates (minor and combined disagreements). This suggests that when adopting a SSSO model, maintaining competency with a wide array of specimens seen on a general intraoperative consultation service may be challenging and warrants careful monitoring of frozen and permanent section discrepancy rates.