There are currently no blood or laboratory tests that have been proven to help in diagnosing sporadic PD.  Therefore the diagnosis is based on medical history and a neurological examination.  The disease can be difficult to diagnose accurately.  Early signs and symptoms of PD may sometimes be dismissed as the effects of normal aging.  The physician may need to observe the person for some time until it is apparent that the symptoms are consistently present.  Doctors may sometimes request brain scans or laboratory tests in order to rule out other diseases. However, CT and MRI brain scans of people with PD usually appear normal.  Since many other diseases have similar features but require different treatments, making a precise diagnosis as soon as possible is essential so that patients can receive the proper treatment.