This SBIR research effort is aimed at the development and testing of a novel system for blood analysis that utilizes MEMS fabricated chips and multiple, radio-frequency electric impedance interrogation signals to differentiate cell types. Our long-term goals for the project can be summarized as three: 1) develop an inexpensive CBC analysis system utilizing disposable MEMS-based micro-fluidic chips for physician's offices, 2) miniaturize the electronic hardware and develop a highly portable CBC analyzer utilizing the same core technologies and 3) expand on the basic technologies (by integrating additional cell detection methods) to enhance system capabilities, performance and reliability. As part of the proposed long-term effort, we will fabricate, characterize and commercialize the first generation MEMS mu-CBC Analyzer. To achieve this, the present SBIR proposal addresses miniaturization of the conductance and impedance base cell counting techniques by incorporating disposable, micro-fabricated detectors into relatively inexpensive bench-top analysis systems. The first of three aims will concentrate on designing and micro-fabricating the next generation MEMS flow-chips suitable for proof-of-concept cell counting studies using radio-frequency impedance measurements. The second aim will target the development for the micro-fluidics required to drive the blood through the micro-channel at a flow-rate suitable for single file interrogation of cells. Aim three will focus on additional proof-of-concept studies to demonstrate feasibility of this technology to function as a hematology analyzer. Future work will build upon the results of the present proposal to create a field portable mu-CBC Analyzer based on the same micro-fluidic cell counting chip. We envision these mu-El systems will eventually lead to the development and commercialization of highly portable systems capable of drastically improving the ease (and availability) of administering blood tests (4-6 years). For example, these systems will enable field tests for remote patients with HIV, rapid testing for incoming emergency room patients, and self-administered home blood testing. These future multiple-detector systems will become extremely cost and performance competitive with the state-of-the-art hematology analyzers (6-10 years). To our knowledge, there are no other commercial efforts to develop blood cell counting instrumentation using MEMS-based technology.