The main objective of this Tutorial Review is to approach the modern principles and practices of Analytical Chemistry to Point-of-Care Testing (POCT) systems in order to contribute to improve both the development of new devices and the reliable application of the existing ones. In this article, after contextualization of the topic, POCT systems (POCTs) are fully defined using several approaches. The requirements of a POCT system to be a robust and reliable tool available to patients and medical workers are described as well as their desirable complementary characteristics. In addition, the technical components of POCTs materialized in the implementation of the steps of the analytical processes (sample introduction, sample processing, visual or instrumental detection, and data processing) are outlined. Besides, analytical properties assigned to POCTs and to their quantitative and qualitative results are highlighted. Special emphasis is given to Quality Assurance and Quality Control procedures, which are essential aspects to achieving reliable results. Finally, decision making based on the results obtained with POCTs is discussed as are their benefits and drawbacks.