The goal of rHEALTH sensor is a universal handheld sensor that can provide rapid, low-cost complete blood count (CBC) with differential, electrolyte analysis, and potential for advanced lab tests such as biomarker analysis all in one single microfluidic sensor. The first innovation is that the device can perform multiple lab measurements in a single microfluidic device. Most sensors can only perform one test at a time, such as CBC analysis. Adequate health monitoring requires at the minimum measurement of CBC and electrolytes. Second, our microfluidic chip is reusable because of its flow-through design. This minimizes cost and obviates the need for bulky consumables. Third, our sensor uses fluorescent analyte sensing dyes and fluorescence technology, which allows the sensor to measure a broad range of analytes. In Phase I, we plan to fabricate a prototype microfluidic sensor and test it for its ability to perform both CBC and electrolyte measurements. Upon proof-of-principle, in Phase II, our goal is to complete and deliver a prototype rHEALTH sensor for NASA to monitor astronaut health on a routine and cost-effective basis.