In modern medicine, physicians routinely judge test results (e.g., blood pressure, triglycerides, etc.) according to certain standards of judgment, and make diagnoses and treatments based on these judgments. This study analyzes the historical background of the creation of standards for judging test results in Europe, the U.S., and Japan from the 19th to 21st centuries, and how it was justified to regard certain values as the boundary between “health” and “disease” or “normal” and “abnormal,” in order to elucidate the factors that made medical care based on test results became commonplace. It also examines the relationship between the act of judging test values and the power systems that lead people to a particular way of life such as “health”. Some of this research findings have been published in the journals Archive for Philosophy and the History of Science and History and Philosophy of Science.