How is a conclusive Alzheimer diagnosis made?

The diagnosis of Sydenham's chorea is usually based on a combination of a recent history of a streptococcal infection and the doctor's observation of the patient's involuntary movements.

Diagnosis of orthostatic intolerance is made when a patient experiences a decrease of blood pressure (not exceeding 20/10 mm Hg) when attempting to stand and a heart rate increase of less than 30...

Laboratory tests often show normal results. Some nonspecific indicators of inflammation may be elevated, including white blood cell count, erythrocyte sedimentation rate, and a marker called...

By laboratory tests called ELISA and Western blot.

Measles infection is almost always diagnosed based on its characteristic symptoms, including Koplik's spots, and a rash which spreads from central body structures out towards the arms and legs.