PROJECT SUMMARY/ABSTRACT This career development proposal is designed to provide Fred Ketchum, MD, PhD, with the necessary training to become an independent clinician-scientist developing interventions to improve decision- making and communication about preclinical biomarker testing that are inclusive to the needs of diverse patients with Alzheimer’s Disease and Related Dementias (ADRD). Dr. Ketchum will build upon his existing skills in qualitative research and medical communication to acquire additional skills in 1) user- centered design and implementation based on healthcare systems engineering approaches; 2) design and conduct of clinical trials of behavioral interventions with racially and ethnically diverse populations; 3) training in decision sciences. As an early-career researcher at an institution with an extensive infrastructure to support early-stage investigators and committed expert mentors, Dr. Ketchum is in an ideal environment to complete the proposed research and training. This proposal seeks to develop and pilot test an intervention to support decision-making about blood biomarker testing in primary care settings. Rapid advances towards blood biomarkers to screen for preclinical Alzheimer’s Disease are a major step towards addressing the devastating consequences of this condition by reducing diagnostic delays, broadening access for diverse populations, and ultimately allowing disease modifying therapies to be started sooner. Blood biomarker testing is expected to be used heavily by Primary Care Providers (PCPs), who make initial decisions about screening, diagnosis, and referral for patients with cognitive complaints. However, decisions about testing are complex, and there is a crucial need to support decisions among PCPs and their patients to address the gap between the future availability of biomarkers and integration into routine diagnostic decisions by PCPs, thereby advancing NIA’s strategic priority of developing effective interventions to address the burden of age- related diseases like ADRD. Aim 1 seeks to characterize decision-making processes related to clinical evaluations for cognitive complaints and identify decision-support needs among patients and PCPs. Aim 2 will adapt a decision-support tool for blood biomarker testing for use in diagnostic evaluations of cognitive complaints by PCPs in diverse populations through a user-centered design process. Aim 3 will test usability and acceptability of the intervention, and effects on shared decision-making. These data will support submission of an R01 proposal at the end of this award to determine the effects of the decision support tool on shared decision-making about blood biomarker testing in preclinical Alzheimer’s Disease in a large national sample.