Bruce Abrahamse

Bruce Abrahamse

July 31, 2024

Alzheimer’s blood test catches 90% of early dementia cases, study finds

In 2020, it was estimated that over 55 million individuals suffer from dementia worldwide. Research suggests that this number is further estimated to double every 20 years. [1] This is why doctors must be able to detect individuals with the potential to develop Alzheimer’s as early as possible. This way, they can enter them into trials that test new treatments as soon as possible, improving the chances of the treatment being more effective. [2] A study has found that a blood test for Alzheimer’s has a 90% rate of accuracy in determining whether an individual’s loss of memory is caused by Alzheimer’s

The Significance of the Alzheimer’s Blood Test

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The remarkable accuracy of this blood test for Alzheimer’s is regarded as rather significant. In comparison, memory specialists typically only correctly diagnosed 73% of their Alzheimer’s cases. According to the study, primary care doctors faired even worse, with only 61% of these doctors correctly diagnosing their cases. The blood test contains p-tau217 (plasma phosphorylated tau 217), among several blood biomarkers researchers are exploring for diagnosing mild cognitive impairment and early-stage Alzheimer’s. [3]

Tau Protein 217

 taking test tube out of centrifuge for plasma in modern clinic
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The blood test for Alzheimer’s disease measures tau protein 217 as it is considered an excellent indicator of amyloid pathology. A profound increase of p tau-217 concentrations has been observed in the blood of individuals with Alzheimer’s disease. [4] Levels have been measured to be up to eight times higher compared to seniors without Alzheimer’s disease. The presence of tau tangles and beta-amyloid in an individual’s brain is typically associated with Alzheimer’s disease. A similar blood test proved to be up to 96% accurate when it came to detecting raised beta-amyloid levels. It was likewise 97% accurate in picking up tau 217. 

The Blood Test for Alzheimer’s Study

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In the study, the test for p-tau217 was combined with another Alzheimer’s blood biomarker known as the amyloid 42/40 ratio. This particular biomarker measures two types of amyloid proteins. The study has found that this blood test for Alzheimer’s is the most effective test for recognizing these early symptoms. The study found that the combination of the tau and amyloid tests proved to be the most predictive, naming it the ‘amyloid probability score’. They aim to develop a blood test that can be administered in a physician’s office similar to a cholesterol test. 

How This Blood Test for Alzheimer’s Works

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The peptide p-tau217 can only be picked up when amyloid plaques are present in an individual’s brain. [5] This means that when researchers measure the levels of p-tau217, they are able to identify early neuronal damage from tau. However, this is only if amyloid plaques are already present. The Alzheimer’s blood test doesn’t measure amyloid directly, yet it can still indicate that it is there. Simply put, if amyloid plaques aren’t present, this suggests that Alzheimer’s isn’t present. However, if there’s elevated tau in the brain without amyloid, it suggests a different type of dementia. 

The Waiting Game

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By 2033, patients could potentially face a daunting six-year wait before finding out if they qualify for treatments. This is if doctors continue to rely solely on the existing cognitive assessments for diagnosing dementia. However, the study found that these waiting times could drop to somewhere between 6 and 13 months if accurate blood tests were used. This is because there would be fewer individuals who would need to go in for additional tests or to see a specialist. However, this is unlikely to happen anytime soon, as more research is still needed to verify all of the results. 

Preventative Measures

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The main goal for these researchers is not only to help with early Alzheimer’s diagnosis in individuals at risk but to likewise evaluate responses to risk-reducing interventions. However, until their goals are achieved, there are other measures that people can take to try to prevent cognitive decline. Research has shown that eating a Mediterranean-style diet, getting regular exercise, and treating vascular risk factors can help slow down or prevent cognitive decline. 

The Bottom Line

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Nothing is quite as painful as witnessing the cognitive decline of a loved one. Thankfully, with the advances in modern medicine and science, we should soon be able to detect these diseases early enough to incorporate treatments that slow down or prevent the disease from worsening. This new blood test for Alzheimer’s is proving to be what researchers have been waiting for. However, until further studies have proven its efficacy, it is suggested that you make a few lifestyle changes that can potentially result in many more years of good mental health. 

Read More: Neuroscientists Warn of “Cascading” Alzheimer’s Risk From These Two Habits

Sources

  1. Dementia statistics.” Alzint
  2. Why spotting the early signs of dementia is so important.” Alzheimers Society
  3. Plasma phosphorylated tau 217 in preclinical Alzheimer’s disease.” NCBI. Erin M Jonaitis, et al. March 6, 2023.
  4. Plasma phospho-tau in Alzheimer’s disease: towards diagnostic and therapeutic trial applications.” NCBI. March 2023.
  5. Present and Future of Blood-Based Biomarkers of Alzheimer’s Disease: Beyond the Classics.” Science Direct. Marina Mantellatto Grigoli, et al. May 1, 2024.