The Food and Drug Administration has given approval for a blood test that will rule out if someone has Alzheimer’s disease and other cognitive issues when they have the symptoms of the conditions.

It is called Elecsys pTau181 and is made by Roche Diagnostics in collaboration with Eli Lilly.

The test measures pTau181 in the blood and would be used with other tests. Higher levels of the protein are linked to Alzheimer’s disease and other neurodegenerative diseases.

The way it works is when someone shows signs of Alzheimer’s or another cognitive issue, a doctor can perform the test. A positive result will then indicate that more testing is needed, CNN reported.

A negative test would mean that a patient would need a different treatment.

tests, the company said in a news release.

Experts warn that it isn’t the only diagnostic tool.

“To more accurately stage disease and track progression over time, I never order one single test. I only order a panel of tests. We’re not at the time yet where one marker is the ‘be all and end all.’ It’s more complicated than that,” preventative neurologist Dr. Richard Isaacson said.

The study involved 312 people, with the new test correctly indicating people without Alzheimer’s pathology in 97.9% of cases.

Still, Isaacson said, “We have to be very cautious with mass adoption of these blood tests because of the potential false positives. The medical field is still learning how to use these tests and how to apply these test results in clinical practice.”

For more on the test, click here.

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