Usually, the outward symptoms of Parkinson's are distinctive enough for a doctor to make a diagnosis in the office. There is no blood test or brain scan that confirms the diagnosis. But if you don't respond to the drugs used to treat Parkinson's disease, it’s possible you may have another type of movement disorder that causes the same type of symptoms. Doing additional tests can help your doctor determine if some other problem is causing your parkinsonian symptoms.
In some cases, your doctor will have you try a medicine for
Parkinson's disease. If that medicine helps your symptoms, it may help the
doctor find out if you have the disease.
There are no lab
tests that can diagnose Parkinson's.
But if your doctor isn't sure you have Parkinson's, he or she may do certain tests to see if you have another condition with similar symptoms.
blood tests may be done to check for abnormal thyroid hormone levels or liver
damage. An imaging test (such as a
CT scan or an
MRI) may be used to check for signs of a
stroke or brain tumor.
Another type of
imaging test, called
PET, sometimes may detect low levels of dopamine in
the brain, a key feature of Parkinson's. But PET scanning isn't
commonly used to evaluate Parkinson's because it's very expensive, not available in many hospitals, and only used experimentally.