1. Blood staining and testing procedure optimization: A 5-part WBC differential (Lymphocyte, Monocyte, Neutrophil, Eosinophil, and Basophil) assay using a staining cocktail of FTIC, PI, and Basic Orange 21 has been developed. The differential capability has been investigated with a correlation study with a commercial hematology analyzer and further verified with purified individual WBC types. In addition, a specific assay was developed for the differential count of the rare population, Basophil, using the fluorescent dye BO21. 2. Verification of the differential assays with purified WBC types. A procedure of preparing purified WBC individual types (Lymphocyte, Monocyte, Neutrophil, Eosinophil, or Basophil) has been developed. The differential capability of the 5-part assay (PI, FITC, BO21) and the Basophil specific assay (BO21) was verified with the purified WBC types. The staining pattern observed from the purified WBC types also provided a useful tool to study new assays. 3. Spectrum analysis capability. One unit of the prototype has been upgraded from two-color detection to spectrum analysis with a commercial mini-spectrometer. Fluorescence spectrum measurment of dye (Acridine Orange) stained white blood cells were successfully demonstrated on the microfluidic chip. Distinct spectrums were measured from the Lymphocyte, Neutrophil, and Eosinophil cells. In addition, the detection of lymphocyte subtype cells were also demonstrated with the spectrum measurement system, which paved the way for simultaneous measurement of multiple subtype cells. 4. Planning for the new generation cartridge. Components of the next generation cartridge were successfully demonstrated. In the current cartridge, manual handling was involved to process the blood sample before test, and an external pump and waste collection tube were need for the fluidic operation. In the next generation cartridge, the whole test will be integrated into a 1cm x 1cm x 3mm chip without external fluidic connection. We successfully demonstrated the on-chip staining of blood sample with fluorescent dyes on the microchip. Besides, basic components of on-chip pump, on-chip valve, and long term reagent storage capability were also demonstrated.