Could a Blood Test Help Detect Alzheimer’s Disease?

Ellen Diamond, (2021, November 10). Could a Blood Test Help Detect Alzheimer’s Disease?. Psychreg on Neuropsychology. https://www.psychreg.org/blood-test-help-detect-alzheimers-disease/

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Routine blood tests offer medical professionals a wealth of information about patient health and assist in the early detection of cancer, diabetes, and heart disease. New research suggests that neurodegenerative diseases like Alzheimer’s may also be detectable through blood tests.

Identifying Alzheimer’s risk using proteins

There are two specific proteins known to be found in aggregated ‘clumps’ in Alzheimer’s patients. They are amyloid-beta and tau, and the relationship between the two is a matter of ongoing research. A study at Washington University School of Medicine first showed that amyloid in the brain can produce excess tau. Because of this excess production, people with Alzheimer’s disease can have heightened tau levels in their spinal fluid. Tau is typically produced and stored inside cells, but tau build-up outside of cells has also been observed in Alzheimer’s patients.

This excess, extracellular tau build-up is widely believed to be a product of dying neurons releasing proteins as they break down. Alzheimer’s causes the accelerated death of brain matter, so this would be a logical explanation for such tau build-ups. However, it has also been proposed that live neurons could be producing and releasing more tau than usual as a symptom of Alzheimer’s.

For many years, doctors were finding these protein build-ups during an autopsy. However, because the protein aggregations could only be observed postmortem, their presence was not considered a viable method for early detection of Alzheimer’s disease.

But what if there was a blood test that could detect elevated levels of these proteins before the symptoms of Alzheimer’s ever popped up? 

Finding phosphorylated tau with blood testing

Detection of Alzheimer’s disease is becoming more accessible thanks to a better understanding of tau proteins and how they work as possible indicators of Alzheimer’s. While routine blood work cannot find tell-tale amyloid or tau proteins locked inside of brain cells or spinal fluid, modern blood testing methods can reveal a particular form of tau in the bloodstream.

Phosphorylated tau protein can be measured in the blood, and it has shown promise as an important biomarker, one that could be an early indicator of Alzheimer’s. In addition, specialized lab tests using advanced methods like protein denaturation can be conducted after taking a blood sample to unlock additional health information.

A blood test may be capable of finding elevated phosphorylated tau levels years before any noticeable memory loss, or other Alzheimer’s symptoms occur, allowing patients and families time to prepare for the possibility of Alzheimer’s and living with mental decline.

Alzheimer’s testing: the old way 

Alzheimer’s diagnoses up to this point have largely been based on subjective measures of a patient’s mental acuity.

Symptoms that suggest someone may be experiencing the onset of Alzheimer’s disease:

  • Memory loss
  • Difficulty concentrating
  • Confusion
  • Lost sense of time
  • Visual or spatial difficulties in navigating environments
  • Language and vocabulary problems
  • Social withdrawal
  • Poor decision-making
  • Mood changes

But by the time a person experiences these symptoms, mental decline has already taken place. 

Early Detection Is Key

The promise of earlier Alzheimer’s detection through simple blood tests is positive news. When patients and families can know the risk of Alzheimer’s before the onset of symptoms, they can plan, prepare, and even begin treatment to slow the progression of the disease.


Ellen Diamond did her degree in psychology at the University of Edinburgh. She is interested in mental health, wellness, and lifestyle.


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