Alzheimer’s blood test could be used to screen even before symptoms: Study

A new blood test screening for signs of Alzheimer’s disease may soon be able to detect it even before symptoms begin to show, a study finds.

The research, published in the JAMA Neurology journal on Monday, found blood tests screening for a protein called phosphorylated tau “accurately identified” biological Alzheimer’s disease. The study, which included 786 participants, indicated Alzheimer’s disease could be detected using these blood tests instead of costly brain scans.

The study evaluated how effective the ALZpath p-tau217 test was in detecting Alzheimer’s disease pathologies, the researchers said.

“This is an instrumental finding in blood-based biomarkers for Alzheimer’s, paving the way for the clinical use of the ALZpath pTau 217 assay,” co-authors Kaj Blennow and Henrik Zetterberg said in a statement. “This robust assay is already used in multiple labs around the globe.”

The study found that testing for elevated levels of the beta amyloid was up to 96 percent accurate and testing for tau was up to 97 percent accurate.

The researchers said blood testing could lead to more rapid screening in patients.

“In primary care, it is estimated that more than 50% of patients with cognitive impairment remain undiagnosed or incorrectly diagnosed because of the lack of accessible and cost-effective tools. Thus, blood biomarkers are set to revolutionize clinical care by providing objective biomarker-based information,” the study stated.

According to the Mayo Clinic, brain imaging, such as MRI scans, CT scans or PET imaging, are often used to help diagnose Alzheimer’s disease in patients. The Mayo Clinic noted that laboratory blood tests can sometimes be used to detect amyloid and tau levels, but that the tests “aren’t widely available and coverage may be limited.”

The Centers for Disease Control and Prevention (CDC) says Alzheimer’s is the most common form of dementia. The agency defines it as a “progressive disease beginning with mild memory loss and possibly leading to loss of the ability to carry on a conversation and respond to the environment.”

In 2020, the CDC said up to 5.8 million Americans were living with Alzheimer’s.

—Updated at 2:54 p.m.