Levodopa Test

What is the levodopa test?

Parkinson’s disease is caused by certain nerve cells not working properly in the part of the brain that makes dopamine, a chemical messenger that helps control body movement. Parkinson’s disease can be difficult to diagnose because symptoms of the condition are similar to those of other movement disorders.

One way a doctor can determine if a person has Parkinson’s disease or a different movement disorder is to give the person a medication that supplements the body’s dopamine supply. Usually doctors give a medication called carbidopa/levodopa.

If carbidopa/levodopa improves the patient’s symptoms, the patient likely has Parkinson’s disease. Levodopa has little or no effect on other movement disorders.

This is one of the key distinguishing features between Parkinson’s disease and other movement disorders.

It is important to remember that the levodopa test is not 100 percent accurate, and it is not used to definitively diagnose Parkinson’s disease. The levodopa test is just one of many diagnostic tools the medical team will use to help in medical management.

What happens during this procedure?

The test, which is given at least eight hours after the patient’s last dose of dopamine supplements, usually takes place in the morning. Symptoms before taking dopamine supplements are scored on a motor scale and scored again after the patient takes a usual dose and waits for an hour.

How long will the test take?

This test generally takes 60 to 90 minutes.

What preparations are needed before a levodopa test?

A patient undergoing a levodopa test should prepare in the following ways:

  • Fill out all required forms before coming in for the appointment.
  • Bring Parkinson’s disease medications.
  • Be sure the doctor is aware of all medications the patient is taking.
  • Leave valuables at home.
  • Bring a book to read while waiting.

Does a levodopa test cause discomfort?


What will happen after the test is complete?

We will discuss what we have learned from performing this test and how it affects the medical management of the movement disorder.

For an appointment, a second opinion or more information, please call 1-800-CEDARS-1 (1-800-233-2771) or email us at neurologicaldisorders@cshs.org.