The medical profession is a very large system that encompasses hundreds of different subspecialties. In general, general hospitals are roughly divided into internal medicine, surgery, obstetrics and gynecology, infection and pediatrics. However, the larger the hospital, the more detailed the subspecialties are. The advantage of this is that doctors who have a narrow but deep scope of study are very specialized in a certain type of disease (especially rare diseases), which helps to improve the diagnosis and treatment of such diseases. There is also a group of doctors called general practitioners, as the name implies, who have a broad but shallow knowledge of the fundamentals of multiple disciplines. Generally, they work in primary care hospitals, and their main task is to make a preliminary judgment and guide the direction of patients. These are called clinicians. They are the ones who deal directly with the patient and are the decision makers for treatment. There is another category of doctors who specialize in blood, urine and fecal tests, pathology reports, photographs, echocardiograms and other examinations to provide clinicians with all kinds of examination and testing information for decision-making. Some patients are not quite sure about these classifications and ask their own questions when they see people in white coats. This is because the division and responsibilities of the various types of doctors were not clarified. Although they get some responses, they are not always the best.