Diagnosis in healthcare is among the most important processes since the protocol for patient treatment depends on this step. Even more, health research and policy draw on this area for their validity. For instance, payment policy, allocation of financial and other resources, and research focus are determined largely by diagnoses. Diagnosis depends on a framework of clinical reasoning, or what is termed clinical decision-making. It has been described as a "pre-existing set of categories agreed upon by the medical profession to designate a specific condition."
The importance of diagnosis in patient care is dependent on its accuracy, reliability, and timeliness, all of which make key contributions to the health outcome. The importance of diagnosis is only highlighted in the case of infectious disease since undiagnosed patients can spread the infection to others.