A medical history is an important diagnostic tool. It allows the physician to eliminate certain diagnoses and add others based on conditions the patient has previously been treated for, the medical conditions that the patient's relatives have suffered from, and other characteristics such as age and physical condition that can indicate the onset of disease.

A simple history generally includes

- The patient's age, race, weight, height and other physical characteristics.

- Any diseases the patient is currently being treated for, and any diseases recently suffered by the patient.

- Information about the health of the patient's parents, including at what age they died and from what.

A more thorough history can include

- All the diseases, including childhood diseases, the patient has suffered from.

- The patient's vaccination history.

- Information about the health of siblings and other blood relatives.

A medical history is usually vital to determine whether a patient suffers from a genetic disorder, as these run in families or only affect people in certain cultural groups.

Importance Edit

Even seemingly minor details can result in a definitive diagnosis being overlooked. In one episode, House sends two students to take a history of a patient. When they come back with a conflicting story about how the patient was injured, House asks what the patient's weight is and what color her nose is. As it turned out, the patient's injury was irrelevant to her condition, which only occurs in persons who are undernourished or alcoholic.