Differential Medical diagnosis

The approach to differential diagnosis is based on the process of finding as many candidate diseases or conditions as possible that could cause signs or symptoms, and then eliminating or at least making the entries more or less likely through further medical testing and other treatments,aiming to reach only one.The extent to which a candidate disease or condition may still be present.The result may also still be a list of possible situations, ordered by probability or severity.Such a list is usually generated by a computer-aided diagnosis system.The diagnostic opinion obtained by this method can be regarded more or less as a diagnosis of exclusion.Even if it doesn't cause a single possible disease or condition, it at least rules out any imminent life-threatening conditions.Unless the provider determines a condition exists, further medical testing,such as medical imaging, will be performed or ordered to partially confirm or refute the diagnosis, but also document the patient's status and keep the patient's medical history up to date.If an unexpected finding occurs along the way, the original hypothesis may be ruled out, and the provider must then consider other hypotheses.

Pattern recognition 

In the pattern recognition approach, providers use experience to identify patterns of clinical features.It is mainly based on certain symptoms or signs associated with certain diseases or conditions and does not necessarily involve more cognitive processing involved in differential diagnosis.This may be the primary method used when the disease is "obvious," or the provider's experience may enable him or her to recognize the condition quickly. In theory, a certain pattern of signs or symptoms could be directly related to a certain treatment, even without a definitive decision on what the actual disease is, but this compromise carries a significant risk of missing opportunities that actually have a different treatment diagnosis, so it may be limited to cases where no diagnosis can be made.