Diagnosing Parkinson disease may be difficult, particularly in the early stages of the disease when symptoms resemble other medical conditions, this can cause for you to not be diagnosed with parkinsons when you really might have it.(a misdiognosis) No single laboratory test can diagnose the disease. Blood tests are performed to eliminate some conditions, which may result in slowness of movement. Brain imaging techniques, help doctors exclude other medical conditions, such as stroke or brain tumors, that produce symptoms that can be mistaken of Parkinson disease. Doctors ask patients about their exposure to drugs, viruses, and environmental toxins to determine if a particular factor may be causing a parkinsonism disorder. They document the medical history of the patients blood relatives to determine the likelihood of a genetic predisposition for Parkinson disease or other disorders. And they carefully observe a patients muscular activity over a period of timeas the disease progresses, motions particular to Parkinson disease become more obvious.

Doctors usually diagnose Parkinson disease if a patient develops two or more of the principal symptoms, at least one of which is tremor or bradykinesia. The diagnosis is usually confirmed if people with suspected Parkinson disease respond well to drug treatment. Those with parkinsonism disorders or other medical conditions with similar symptoms typically do not respond to the drugs used in treating Parkinson disease.