BATON ROUGE — More than seven million people in the United States have Alzheimer's disease.

A blood test recently approved by the FDA may be able to help with early diagnosis.

"The new blood test that's available for Alzheimer's disease is actually measuring a chemical that comes out of the brain and is associated with the amount of plaque, or amyloid protein, that is part of the disease. So it's picking up the pathology of the disease and can do this actually very early in the disease process," Neurologist Dr. Charles Bernick said.

The new blood test is for adults over the age of 55 who are showing signs of Alzheimer's disease.

Symptoms typically include memory loss and a decline in other cognitive abilities, like being able to use logic and language. Experts say an earlier diagnosis gives a patient the chance to start treatment sooner. That improves the odds of delaying or stopping the progression of symptoms.

It is not the only benefit of this blood test.

"We can use these blood tests to help differentiate conditions because often when we see patients in the clinic, we're not sure if they have Alzheimer's disease, or if their memory problems are due to something else. Could be strokes, could be other diseases, such as Parkinson's disease. So these blood tests help us in differentiating what the underlying cause of the disease is," Dr. Bernick said.

The blood test could also speed up the process of finding the right participants for a clinical trial, and that in turn could lead to quicker development of potential medications.