Retrospective diagnosis is practised by medical historians, general historians and the media with varying degrees of scholarship. At its worst it may become "little more than a game, with ill-defined rules and little academic credibility." The process often requires "translating between linguistic and conceptual worlds separated by several centuries", and assumes our modern disease concepts and categories are privileged. Crude attempts at retrospective diagnosis fail to be sensitive to historical context, may treat historical and religious records as scientific evidence, or ascribe pathology to behaviours that require none. The understanding of the history of illness can benefit from modern science. For example, knowledge of the insect vectors of malaria and yellow fever can be used to explain the changes in extent of those diseases caused by drainage or urbanisation in historical times.
The practice of retrospective diagnosis has been mocked in parody, where characters from fiction are "diagnosed". Squirrel Nutkin may have had Tourette syndrome and Tiny Tim could have suffered from distal renal tubular acidosis (type I).
The term retrospective diagnosis is also sometimes used by a clinical pathologist to describe a medical diagnosis in a person made some time after the original illness has resolved or after death. In such cases, analysis of a physical specimen may yield a confident medical diagnosis. The search for the origin of AIDS has involved posthumous diagnosis of AIDS in people who died decades before the disease was first identified. Another example is where analysis of preserved umbilical cord tissue enables the diagnosis of congenital cytomegalovirus infection in a patient who had later developed a central nervous system disorder.