Background: Inequities in NGS testing in pts with aNSCLC are well documented. Here, we examined elements of total inequity in NGS testing for pts with aNSCLC treated in the US community setting, in terms of within and between inequities at the practice and provider level. Methods: Using the nationwide, deidentified, electronic health record–derived Flatiron Health database, we studied pts with aNSCLC diagnosed in April 2018 or later and treated in the community setting. Testing quality was defined as an NGS result reported ≤60 days after advanced diagnosis. Total-practice inequity was the average percentage-point (pp) difference in the rate of testing quality for non-Latinx Black or Latinx pts compared with non-Latinx white pts. Within-practice inequity was the average pp difference in testing rates at a practice weighted by overall practice enrollment. Between-practice inequity was the covariance between a practice's overall testing rate and the extent of practice-level racial/ethnic underrepresentation. We estimated these inequities at the practice and provider levels using a Bayesian approach. Results: Our study included a total of 12,045 pts (9,981 non-Latinx white, 1,528 non-Latinx Black, and 536 Latinx pts). Both within- and between-practice inequities contributed to total inequity in NGS testing for non-Latinx Black and Latinx pts compared with non-Latinx white pts (Table). For non-Latinx Black pts, between-practice inequities were estimated as 57% (3.77 pp/6.56 pp) of the total inequity in NGS testing; for Latinx pts, the contribution of between-practice inequity was 39% (3.13 pp/8.01 pp). At the provider level, between-provider inequities were the dominant contributor to total inequity in NGS testing for both non-Latinx Black and Latinx pts, accounting for 86% (5.88 pp/6.87 pp) of total provider-level inequity for non-Latinx Black pts and 64% (5.36 pp/8.43 pp) for Latinx pts. Conclusions: Inequities within and between practices, as well as between providers, are meaningful contributors to total inequity in NGS testing. Additional healthcare equity initiatives are needed to identify potential causes for lagging practices/providers to address inequities in NGS testing.

* Negative values indicate higher NGS testing rate in non-Latinx Black or Latinx pts vs non-Latinx White pts.