Making the Diagnosis

Currently, the diagnosis of Parkinson’s disease is purely a clinical one. This means it is based on:

This surprises many people, given the medical tests, laboratory work and imaging studies that are used to diagnose other conditions.  This may change in the future, since the FDA recently approved a new imaging technique called the DaTScan.

The diagnosis of Parkinson’s is usually done by a neurologist or a movement disorder specialist. The following criteria are used in determining if a person has Parkinson’s disease:

Medical History and Examination

Two of the three movement problems must be present:

Other features that are helpful in diagnosis:

Non-movement symptoms that can precede movement symptoms can be a clue to early diagnosis.

Medical Tests:

Laboratory tests

Blood and urine copper studies can be helpful in younger people to test for Wilson’s disease (a genetic condition associated with abnormal body tissue copper levels.)

Vitamin B12, vitamin D, thyroid levels, blood count and metabolic panel are labs that can help identify additional cause (unrelated to Parkinson’s) for symptoms of fatigue, depression, and cognitive change.


Brain Imaging

Brain MRI scans does not typically reveal problems in Parkinson’s and is therefore not routinely done.  However, other conditions such as stroke or normal pressure hydrocephalus can be identified.  These conditions are described in the related article atypical parkinsonism.

DaTSCAN is a nuclear medicine brain image depicted below that measures the amount of dopaminergic nerve cells in the basal ganglia. However, at this point the scan is not able to diagnose Parkinson’s disease from atypical Parkinson’s so may not help with diagnosis.  It will help differentiate Essential or familial tremor from tremor caused by Parkinson’s disease.