Background: Circulating tumor DNA (ctDNA) for detection of MRD in resected CRC is a prognostic factor for recurrence. However, current utilization of available commercial tests has not been investigated. We report real world clinician use of a validated, plasma-only, multiomic MRD assay (Guardant Reveal) in a large unselected CRC cohort. Methods: Results from Guardant Reveal MRD testing ordered for clinical care in the US were retrospectively queried for the first 2,000 consecutive CRC cases. Pts could be enrolled in a post-operative program to inform adjuvant treatment (PostOP, up to 3 tests within 3-16 weeks post-resection) or a surveillance program (SP) for recurrent tests post-treatment. Pts could have tests across both programs and/or one-time tests. All subsequent tests for the first 2,000 patients were included for analysis (data cut-off: 1/15/2022). Recurrent programs were analyzed for stage (stg) II/III only. Clinical factors were derived from test requisition forms. Results: 2681 tests from 1993 pts were analyzed; 7 pts were excluded due to missing cancer stage. Median age was 64 years (range: 21-65), 55% were male, most (94%) had stg II/III disease (Table). ctDNA was detected in 25% of all pts; detection increased with stage (Table) as expected. Among stg II/III pts, 330 (21%) had only PostOP test/s, 950 (51%) SP only, 54 (3%) had both PostOP and SP; the remainder had one-time test/s outside defined programs. In Stg II/III pts with >1 PostOP test (26%/17% respectively), ctDNA was detected in 102/384 (27%), of whom 72% had it detected on the first test. The median time from surgery to first result was 5 weeks (10 weeks for a second result). 95% of all stg II/III pts had results from PostOP testing before week 12 post-resection. In Stg II/III pts with >1 SP test (47%/54% respectively), ctDNA was detected in 244/1024 (24%), of whom 87% had it detected on a first test. The average time from date of surgery to first surveillance test was 305 days (median: 489, range:51-4618). Conclusions: ctDNA detection rates by a plasma-only multiomic MRD assay in this large CRC clinical cohort are similar to published rates. ctDNA orders by clinicians were most frequent in Stg II/III surveillance settings followed by PostOp, consistent with the population size of eligible patients for PostOp vs. Surveillance use-case. Importantly, nearly all pts tested PostOP had results prior to 12 weeks post-resection, which may inform adjuvant therapy decisions. These findings should be correlated with clinical outcomes to improve the utilization and utility of MRD testing in adjuvant management of CRC.