11175 Background: Biomarker testing informs treatment decisions by identifying patients who would clinically benefit from targeted regimens, leading to improved patient outcomes. However, the use of guideline-recommended biomarker testing in patients with advanced non-small cell lung cancer (NSCLC) is inconsistent. This study investigates the rates of biomarker testing in patients with NSCLC using a qualitative, real-world database. Methods: Natural language processing (NLP) was used to search and analyze the Amplity Insights database, consisting of transcribed, de-identified, records of physician-patient interactions obtained from patient medical records across the United States. This was a retrospective analysis of patients with a diagnosis of NSCLC (October 2003 - November 2023). Patient characteristics, biomarker testing, and treatment use were summarized and described. Results: 61,018 patients with NSCLC (mean [standard deviation] age of 69.8 [10.5] years) were identified. Among these, 50.6% were female and 87.9% identified as white. Among records with staging information, 26.6% had early-stage disease (stage 0-II) and 73.4% had late stage (stage III-IV) disease. In total, 13.4% (n=8,151) of all patients received biomarker testing. 13.3% (n=879) and 22.4% (n=2,402) of patients with stage III and IV, respectively, had biomarker testing performed; rates were higher in patients who were receiving care from an oncologist (16.8%, 31.0%, respectively). Among patients who had a confirmed actionable mutation (n=6,387), 35.9% received an appropriately matched targeted therapy and 10.1% received a nonindicated targeted therapy without harboring the indicated mutation. Of these, 40.7%, 22.7%, and 37.7% of patients harbored EGFR or ALK mutations, or were PD-L1 positive, respectively, and 35.8%, 17.8%, and 40.2% received the appropriate indicated treatment, respectively, based on testing. ALK-, EGFR-, and PD-L1-targeted therapies were taken by 12.1%, 9.4%, and 1.9% of patients, respectively, without evidence of the indicated biomarkers. Conclusions: These findings suggest that biomarker testing may be underutilized and that many patients may not be benefitting from treatment with precision therapies, highlighting the need for additional educational strategies to optimize precision oncology and elevate patient outcomes.