Background: Biomarker testing is necessary for optimal 1^st line treatment selection in advanced NSCLC. Patient understanding of timing and purpose of biomarker testing is imperative for patient engagement in care but is challenging to achieve (1). The 4R Oncology model of patient self-management and timely care delivery has been shown to improve patient knowledge of timing/sequence of care in breast cancer (2) but has not been studied in NCLSC in relation to biomarker testing. 4R is being implemented at 5 centers (3 community and 2 academic) in NSCLC. We report baseline assessment of patient awareness of biomarker testing timing and purpose to inform 4R implementation. Methods: Pre-implementation surveys of patients with advanced NSCLC at 5 centers Aug – Dec 2022. Metrics are listed in Table. Results: Survey response rate: 46% (65/142). Respondents were 65% White, 42% high school educated or less, 46% with annual income ≤$30K. While all patients were aware of receiving non-biomarker tests, >40% were not aware of receiving biomarker testing (Table). About half knew why or how long they need to wait for results, but only 29% received this information from providers. Of those tested, the majority reported provider discussions of biomarkers or therapy selection and were clear about results or therapy selection. Awareness (eg, knowing to wait for results before therapy) was associated with receiving printed NSCLC materials (45% vs 7%, p<.01), education above high school (69% vs 41%, p=.03) and income >$30K (67% vs 32%, p=.01). Willingness to wait for test results was associated with knowing how to prepare for treatment while waiting (89% vs 46%, p<.01). Race did not impact these metrics. Conclusions: Considerable gaps exist in patient awareness of timing and purpose of biomarker testing. We refined the 4R model to emphasize biomarker timing in printed visual material, facilitate patient-provider discussions and engage patients in health maintenance while waiting for results. We revised 4R to a lower literacy level. Results will be reported when available. (1) Martin, Oncol Issues, 2022. (2) Trosman JCOOP 2021.