Background: Concordant with national guideline recommendations for patients with previously untreated metastatic non-small cell lung cancer (NSCLC), we evaluated testing patterns for predictive biomarkers as part of standard diagnostic work-up. Methods: This retrospective, observational cohort study included 50 patients treated in the Utah Cancer Specialists (UCS) network, with an index-date of newly-diagnosed Stage IV non-squamous NSCLC between January 2018 and June 2020. Medical records were Abstracted from charts and an electronic database. The primary objective was to measure the “effective” biomarker testing rate of five major guideline-recommended biomarkers (EGFR, ALK, ROS1, BRAF, and PD-L1), defined as results available to treating physicians prior to initiation of first-line therapy. Secondary objectives were to measure: “overall” biomarker testing rates regardless of timing including NTRK, proportion of patients who received a matched first-line therapy based on biomarker results, tissue biopsy insufficiency rate, time from diagnosis to biomarker test ordered, and turnaround time (TAT) for tests ordered. Results: A cohort of patients (56% male; mean age 70.8 years; 90% White/6% Asian) was identified from 2018 (n=22), 2019 (n=22), and 2020 (n=6), including all those eligible from 1/19-6/20. Effective and overall biomarker testing rates for five major biomarkers in aggregate were the same (66%). Effective biomarker testing rates for individual biomarkers ranged from 6% for NTRK to 70% for BRAF, 76% for ROS1, 82% for EGFR, 84% for ALK and 92% for PD-L1. EGFR and ALK alterations were identified in 21% and 7% of tests, respectively, and 65% had PD-L1 > 1%. All patients with a known EGFR or ALK mutation received a matched first-line targeted therapy (12/12). No genomic alterations were found for ROS1, BRAF, and NTRK. Among the biomarkers, median time from diagnosis to test order was 7-14 days and median TAT was 10-13 days. 14% of tissue samples did not contain sufficient tumor tissue for biomarker testing. In addition to tumor testing, circulating tumor DNA-based liquid biopsy tests were used for 12% of the patients. Conclusions: We found two-thirds of UCS patients newly diagnosed with metastatic NSCLC had all 5 guideline-recommended biomarker test results available to prescribers in time for initial treatment decisions. Future studies at other practices should take into consideration current guidelines as new actionable biomarkers emerge.