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A new blood test may be able to detect Alzheimer’s years before an official diagnosis. The Good Brigade/Getty Images
  • Researchers say they are developing a blood test that can potentially detect Alzheimer’s disease more than 3 years before clinical diagnosis.
  • They say the test could be used to begin Alzheimer’s treatments earlier.
  • Experts say more research is needed, but if the test proves to be viable it could be an important step in Alzheimer’s disease diagnosis and treatment.

Scientists say they have developed a test that can potentially detect Alzheimer’s disease a few years before people typically get a clinical diagnosis.

In their new study, which was published in the journal Brain, the researchers report that their blood-based test could identify atypical brain cell activity in people who may later receive a diagnosis of Alzheimer’s disease.

With Alzheimer’s — a disease that causes memory, language, and cognition issues — the brain starts to change as much as 20 years before symptoms of Alzheimer’s appear.

The medications now available work best when given during the pre-clinical stage, which is why researchers say this type of test could help identify and significantly improve outcomes for people who are in the early stages of Alzheimer’s disease.

“The results are interesting and might provide a new way to assess cognitive progression in people with MCI,” said Dr. David M. Holtzman, a professor of neurology at Washington University School of Medicine in St. Louis and former president of the American Neurological Association.

To understand how neurogenesis is altered in people who develop Alzheimer’s disease, the researchers collected blood samples over the course of 2 to 5 years in 56 people with mild cognitive impairment (MCI).

MCI is often an early indicator of Alzheimer’s disease. In the study, for example, 36 of the 56 participants were later diagnosed with Alzheimer’s disease.

The researchers then treated brain cells with the blood taken from the participants to see how the cells changed when exposed to the blood as participants’ cognitive decline progressed.

The team reported that, among the participants with MCI who subsequently developed Alzheimer’s disease, there was less brain cell growth and division and more cell death.

Those same blood samples also boosted the usual amount of immature brain cells that were converted to hippocampal neurons — a process called neurogenesis.

The researchers suspect the reason for this unexpected neurogenesis is that the brain may be compensating for neurodegeneration or the loss of brain cells.

The researchers said the blood-based test could predict progression from MCI to Alzheimer’s disease more than 3 years before clinical diagnosis.

More research is needed to validate the findings and evaluate the test in a more diverse group of people, the researchers stated in their paper.

“There is quite a bit of additional research that needs to be done before this could be used in the general population, but it is a good step toward trying to find a way to more accurately diagnose Alzheimer’s dementia earlier,” Dr. Jessica Lee, a geriatrician with UTHealth Houston and Memorial Hermann, told Healthline.

According to Holtzman, while some people with MCI have underlying Alzheimer’s pathology in their brain, other people with MCI do not have underlying Alzheimer’s pathology.

There are other causes for their cognitive impairment that can be identified through medical testing.

Holtzman believes it could have been beneficial for the researchers to utilize imaging, cerebrospinal fluid, or plasma biomarkers to identify what was causing the MCI.

“This makes it difficult to know whether the effects of the serum on the in vitro assay predicting cognitive decline was due to underlying Alzheimer’s disease or another cause,” Holtzman told Healthline.

That said, this new report highlights a new, exciting way to potentially detect Alzheimer’s disease early through a low-risk, inexpensive test, says Lee.

Right now, people are only able to receive a probable diagnosis of Alzheimer’s disease through a series of imaging tests, lab studies, memory tests, and physical health assessments.

A definite diagnosis of Alzheimer’s can only be given through a brain autopsy after a person has passed away, says Lee.

“If we were to be able to predict the development of dementia long before then, it would give patients the opportunity to plan ahead of time with respect to their families, finances, and goals,” Lee said.

Scientists have developed a blood-based test that could potentially detect Alzheimer’s disease a few years before people typically get a clinical diagnosis.

The brain starts to change years before Alzheimer’s symptoms appear and this type of test could help identify people in the early stages of Alzheimer’s disease progression.

More research is needed to validate the findings, but the findings bring medical professionals one step closer to understanding a disease that affects more than 6 million people in the United States over the age of 65.