Journal Nature Medicine, highlights how a simple bloodtest

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After years of research, scientific advances made identifying biomarkers of Alzheimer’s, importantly tau protein accumulation in the brain, much easier. However, not without side effects. Either through extracting spinal fluid or undergoing PET scans of the brain, the early diagnosis of Alzheimer’s is invasive, expensive and involves radiation.

A new study funded by the National Institutes of Health (NIH), published earlier this month in the journal Nature Medicine, highlights how a simple blood test could be less time consuming and more convenient in diagnosing pathological Alzheimer’s disease in its early stages. After this blood test, people could undergo clinical trials to explore various treatment options, the researchers hope.
“The development of a blood test would enable us to rapidly screen a much larger and more diverse group of volunteers who wish to enroll in studies,” Richard J. Hodes, M.D., director of NIH’s National Institute on Aging (NIA), said.
What The Study Found
The study was conducted at the University of California in San Francisco by international researchers under the leadership of Adam Boxer, M.D. and Ph.D. They recruited 362 people in the age range of 58 to 70 years. Of them, 56 had Alzheimer’s disease, 190 with frontotemporal dementia (FTD), 47 had mild cognitive impairment and 69 controls without any neurodegenerative conditions.


Blood samples checked for pTau181, the protein causing tangled structures in the brains of Alzheimer’s patients. The results of the blood test showed that pTau181 levels were 3.5 times higher for people suffering from Alzheimer’s compared to healthy participants. Those with mild cognitive impairment had a gradual increase of pTau181 levels when they were followed for two years, accelerating the pace of cognitive decline.
Surprisingly, people with FTD had pTau181 levels within the normal range. When they were checked for another protein called neurofilament light chain (NfL), a biomarker for various neurological diseases, it was shown to be elevated in the blood samples. NfL is necessary to provide structural support to neurons, and when they deteriorate, NfL enters the bloodstream and causes damage to the neurons.
Frontotemporal dementia is characterized by the damage inflicted on the frontal and temporal lobes, often causing problems with emotion, language and decisiveness. Though FTD is less common, it begins earlier, and is considered the most prevalent form of dementia in people aged under 60.
PET scan screening can also identify another protein indicating Alzheimer’s, called the amyloid. The researchers could not predict the onset of dementia using amyloid levels, and they found using pTau181 easier. The researchers said the blood test was as good as PET scans and drawing spinal fluid for both diagnosing early dementia and differentiating between Alzheimer’s and FTD. However, the advantage is that blood tests are cheaper, easier to perform and more convenient.