Nanohmics proposes to develop a handheld blood analyzer for micro- and hypo-gravity missions. The prototype instrument will combine impedance analysis with optical spectroscopy techniques to provide a reliable means of performing a complete blood count (CBC) using microliters of sample. An advantage of this hybrid strategy is that a complete blood cell count can be achieved using a microfluidic approach that is controlled via a commercially available personal digital assistant (PDA). Recent advances in the handheld computing market have led to small, powerful, devices that are able to interface and control the microelectronics necessary to operate and collect data from the microfluidic chip and maintain a low power budget. The instrument will exploit both the optical and impedance properties of the whole blood to gain discrimination of the individual components and indices (RBC, WBC, Hemoglobin concentration, hematocrit, WBC differential, and RBC indices). The large amount memory and processing power afforded by the PDA will allow the device to store the blood profiles of many individuals and track their changes from test to test.