We demonstrate a sample-to-answer nucleic acid testing device. The streamlined nucleic acid sample processing, including DNA extraction, amplification, and real-time detection, are achieved on a single microfluidic reagent disc by actuating the DNA-carrying magnetic beads against stationary reagent droplets. The battery-powered handheld instrument is unprecedentedly integrated with mechanical, thermal and optical subsystems with data connectivity. LCD touchscreen and smartphone connectivity offer a user-friendly interface for easy operation. This versatile platform can be widely disseminated to a variety of other situations that demand portability, connectivity, and ease-of-use.