Your doctor also may check your sense of smell.
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.
For instance, 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.