Computerization and software development are experiencing a great rise. Systems are becoming increasingly complex, and consequently the number of business rules increases. The latter are difficult to handle because they are scattered across the system. They are written in programming languages, therefore only software developers can maintain them. In addition to all of these problems, some of them require a support in decision-making. Some of these problems are solved by business management systems that are used as implementations by the language to define GDL instructions. The same goes for the healthcare industry. The Bachelor’s degree presents the openEHR standard on which the Think!EHR Platform™ platform is based on. Further, the HL7 standard for the exchange of messages in health, and the language of GDL are presented. I demonstrated its functioning with an example. Besides the theoretical basis, the prototype of the system was presented. Components of the Think!EHR Platform™ platform are based on the standards and architecture of the platform and use its support in clinical decision-making. It supports the case of finding an anaemia of a patient with chronic kidney disease in the Think!Clinical system. With the presented topic, theoretical basis, prototype, and a case study I attempted to present and offer solutions to some of the problems in the development of health information systems.