Designed and prototyped a disposable, modular cartridge for the CellularCT diagnostic system to support automated white blood cell processing and imaging. The cartridge was intended for use with a benchtop device combining light microscopy, fluorescence cytometry, and machine learning for disease diagnosis in resource-limited settings. The design focused on modularity, low-cost manufacturing, and reliable fluid handling. Multiple design iterations were developed to improve the cartridge layout, fluid paths, and ease of assembly through prototyping and basic bench testing.