Currently there are limited low cost nucleic acid amplification point-of-care FDA cleared products dedicated for outpatient settings. mFluiDx aims to develop a rapid and fully automated point-of-care nucleic acid diagnostic device (POC-NAAT) to detect major infectious diseases (including drug resistance) in outpatient settings at very low cost. mFluiDx has completed the I-CORPS training (Lean Startup Method), interviewing 200+ experts in the customer ecosystem, validating its product market fit and competitive advantage. mFluiDx's core technology is vacuum-diffusion based microfluidics, termed SIMPLE technology – a fast, low cost and efficient microfluidic technology. In phase I, mFluiDx has developed the world's fastest isothermal assay to a target pathogen (confidential) with comparable analytical sensitivity and specificity compared the PCR gold standards. mFluiDx has also developed sample preparation technology with rapid turnaround time and high efficiency. In this phase II study, we propose to complete the development of the microfluidic diagnostic device and assay reader, as well as expanding the assay panel. The specific aims include developing of primer and probes for multiplex assays, improving assay reaction rate, improving reagent stability during storage, designing for scalable manufacturing, increasing optical signal of the assay, and building an optical reader. Finally, a full workflow will be validated using de-identified pediatric samples provided by collaborators. Two on-site studies will be conducted for proof-of-concept and user interface feedback. Successful commercialization of this technology will serve primary care clinics, and improve patient quality of life while saving medical resources.