2. No definitive test for Parkinson’s exists.
Unlike some other diseases that can be detected through blood tests or imaging scans, no definitive test for Parkinson’s disease yet exists. Instead, doctors diagnose PD with a thorough medical and family history and a physical exam. If a patient exhibits at least two of the three hallmark signs of PD—tremor, muscle rigidity, slow movement—then a doctor will consider a PD diagnosis. Sometimes, to achieve a diagnosis, a doctor may start a patient on a Parkinson’s medicine to see how the person responds. If symptoms improve, then the doctor may diagnose the patient with PD.