The task of the information content of the model of diagnostic medical-biological experiment planning is solved in the article. For this purpose, a detailed analysis of medical diagnostic tasks, including routine ones, was carried out. This analysis showed the necessity of planning such experiments using the information content or risk levels of the first and second types as a criterion. On the basis of the general theory of information, an information model of such an experiment for the case of two diagnosed states has been developed in the work. This model makes possible to quantify the information content of the experiment based on the specified parameters of the experimental design. For automatic information systems with training while working, a model is proposed that takes into account the number of training samples. The obtained models allowed to perform a study of the diagnostic experiment plan for the effect of the plan parameters on the resulting amount of the expected information. Besides, the proposed models allowed optimizing the parameters of the diagnostic experiment plan for the minimum average risk. In the work, the information theory of control and diagnostic solutions for the planning of a medical-biological experiment was further developed by creating mathematical models for obtaining the amount of information, taking into account the type of the experiment design, which allowed to maximize this information by selecting the plan parameters.