Question:

Is Parkinson`s disease diagnosed by blood test, another laboratory test, or by presentation of symptoms?

Answer:

The diagnosis of Parkinson`s disease is made based on the history and the physical examination. Presence of tremor, slowness of movement, muscle rigidity and an asymmetrical onset are the key diagnostic criteria, although not all have to be present. While there are some families in which a specific gene has been isolated (e.g. the alpha-synuclein gene), it is likely that multiple genes may be involved and therefore genetic testing is not useful at present. In younger patients I do obtain blood work to rule out other causes of similar symptoms (e.g. serum ceruloplasmin to screen for Wilson`s disease). However there is no blood test to rule in Parkinson`s disease. Similarly, I often obtain an MRI scan to rule out other causes of similar symptoms (e.g. Normal Pressure Hydrocephalus, or strokes), however, this does not rule in PD. PET scans that analyse the flow of radiolabelled dyes to the brain are helpful in a research setting, but have little application in the clinic, especially given the high cost of the study. A definite response to Sinemet or dopamine agonists is very useful in clinching the diagnosis. In summary, the diagnosis is based on a clinical examination by a physician who is aware of the typical presentations of PD, and by a therapeutic trial of antiparkinson medications.

For more information:

Go to the Parkinson’s Disease health topic.