Cancer is one of the most prominent diseases in the world known for its leading cause in death. Cancer development in the human body is triggered by the persistent upregulated proliferation of cells.—unlike regular cells, which respond to biochemical signals that regulate normal cell behavior, cancer cells grow and undergo division uncontrollably. Once they reach the stage of malignancy, they are able to invade normal tissues and organs and spread throughout the body via the circulatory and lymphatic systems. The process taking place is metastasis, where the benign tumor cells become circulating tumor cells (CTCs) and make their way into the blood stream. According to oncologists, it is crucial to detect and monitor cancer in its early stages with a noninvasive method before the spread of malignant tumors to other body sites enable them to become resistant to localized treatment. In this study, we explore the performance of a developed microfluidic device as a platform to assess the capture efficiency of the THP-1 monocytic leukemia cell line and its adherence to its biomarkers CD45 and CD31 antibodies conjugated on the device under different flow rate conditions. We were able to empirically determine that the flow rate of 8.333 µL /min results in the optimal capture efficiency of the device. It is envisioned that this technology will have applications for tumor biopsies and cell sorting.