The book focuses on protein-based sensing technologies and their applications in health, food safety, and environmental monitoring. It discusses the principles and design of ELISA, LFIA, immunosensors, and enzyme-based sensors as effective analytical tools. The comprehensive text examines the fundamental construction and working principles of these technologies, their implementation in healthcare for clinical diagnostics and pathogen detection, applications in the food industry for identifying adulterants and contaminants, and their utility in environmental assessment for water quality monitoring. Organized in four distinct parts, the book provides in-depth coverage of point-of-care testing methodologies that directly impact human wellbeing across these critical domains. The book for undergraduate, postgraduate, PhD students, researchers and academicians in biotechnology, food science, food science and technology, microbiology, biotechnology, biochemistry, and chemistry.