For example, a patient who came to the emergency department with an acute but severe nosebleed (epistaxis) that had become too difficult to treat at home, so she went to the emergency department. Upon arrival, examination and obtaining a complete history of the patient, it was observed that the patient had been discharged after a recent hospital stay with coumadin, but that she had not undergone any follow-up or any tests to ensure adequate coagulation and that now her blood had become so thin that she was at risk of nosebleed. While in the emergency department, he had an episode of bloody diarrhea and additional tests revealed a ruptured previous gastric ulcer, increasing his risk of death and requiring additional resources for testing and treating a high-risk condition. In this context, the main diagnosis is probably bleeding gastric ulcer, which requires much more resources than acute epistaxis.
A primary diagnosis describes the underlying cause of a patient's admission to the hospital. It is assigned after the completion of diagnostic tests and examinations.
