The FDA clears the first blood test for diagnosing Alzheimer’s disease

There’s a new way to screen for early detection of Alzheimer’s disease. On Friday, the Food and Drug Administration (FDA) cleared the first blood test for the disorder. Fujirebio Diagnostics’ Lumipulse measures the ratio of two proteins that correlate with the presence or absence of Alzheimer’s. Previously, patients being screened for Alzheimer’s were limited to more invasive options: a PET Scan or spinal tap.

Lumipulse is intended for use in clinical settings with patients exhibiting signs of cognitive decline. At least in its current form, it isn’t something the general population can ask for as a standard screening.

The test works by measuring two proteins: pTau217 and β-amyloid 1-42. The blood test calculates their ratio, which correlates with the buildup of amyloid plaques in the brain. People with Alzheimer’s have elevated pTau217 and lower β-amyloid 1-42.

In a clinical study, the test performed better with negative results than positive ones. As such, Reuters reports that the test will likely be used initially to rule out Alzheimer’s. Over 97 percent of negative results corresponded with a negative PET scan or CSF test result. Results for positives were a bit lower: a 91.7 percent correlation. So, positive results will need to be confirmed with more advanced diagnostic tests.