Abstract Introduction : BioFluidica has developed a platform, The Liquid Scan™ to analyze circulating cancer cells in whole blood. The Liquid Scan is unique in its performance metrics compared to existing platforms by employing fully automated instrumentation in conjunction with a highly sensitive and a specific cell detection microfluidic chip. This technology can be applied to a broad variety of tumors, including liquid tumors such as leukemias and lymphomas. The unique design of the microfluidic chip permits the capture and analysis of live circulating leukemic cells (CLCs) from whole blood, even when these cells appear undetectable by other methods. The Liquid Scan has been applied to capture CLCs from patients suffering from acute myeloid, as well as acute lymphoblastic leukemia (AML and ALL, respectively). These leukemias are acute diseases of the blood and bone marrow, with mutational changes and clonal expansion of abnormal myeloid and lymphoblastic precursors, respectively claiming a great number of lives every year. Bone marrow biopsies/aspirations have been the standard methods for reliably diagnosis and monitoring these diseases. These procedures are extremely painful for patients, necessitate specialized centers, and trained personnel, which increases the overall cost of treatment. Methods: We have applied the Liquid Scan™ to capture CLCs and characterization, using specific antibodies to capture known clones of leukemic blasts. As a model, we use Kasumi-1, KG-1 and HL-60 cells for AML, and SupB15 cells for ALL, spiked in healthy whole blood. Results: We characterized the ability of the The Liquid Scan™ to capture and release circulating leukemic cells from whole blood, by using cell line models spiked-in whole healthy donor blood and applied to the microfluidic chip. Our results are directly applicable to patient in different stages of the disease, both as an initial diagnostic tool, and as a way to monitor recovery and diagnose relapse. Conclusions: Precision medicine (PM) is significantly changing the treatment of cancer and is bringing new hope for patients. Diagnostic testing for circulating tumor and leukemic cells are promising prognostic and predictive tools for selecting optimal therapies based on the patient’s genetic content. Highly sensitive, and selective BioFluidica’s system is highly sensitive and selective with the capability of rapidly delivering purified and concentrated circulating cancer cells compatible with downstream molecular diagnostics. Citation Format: Rolf Muller, Rachel Toughiri, Alena Bartakova, Paul Diaz, Craig Carson, Paul Armistead, George Fedoriw, Mathew Foster, Maryam Zomorrodi, Jennifer Barber-Singh, Veronica Cheung, Emily Mirkin, Roksolana Melnychuk, Elizabeth Fabio, Sangeetha Purushotham, Judy Muller-Cohn. A microfluidic platform to capture and detect cancer cells in Leukemia patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4214.