New Alzheimer’s Test Makes Diagnoses 94.5% Accurate

We’ve written before about early Alzheimer’s screening by means of blood tests:

• Early Dementia Screening From Your Blood & More
• How To Actually Access Early Dementia Screening

So, what’s the latest?

Protein P-Tau217 has something to say

Researchers (Dr. Sara Matarranz-González et al.) followed 200 consecutive new patients aged 50 and older with adverse cognitive symptoms to test whether adding a blood biomarker (p-tau217) improves Alzheimer’s diagnosis in routine clinical settings.

In few words: elevated levels of this protein in the blood are one of the most accurate early warning signs of Alzheimer’s.

What it actually is: phosphorylated tau 217 (so, p-tau217) is a form of tau protein that becomes abnormally modified and forms tangles in the brain, inconveniently disrupting communication between neurons, and/but conveniently serving as a highly accurate biomarker of the underlying Alzheimer’s pathology (and thus, a top-tier diagnostic clue).

We wrote a bit about tau tangles before, here: Spermine vs Alzheimer’s & Parkinson’s!

As for the accuracy of p-tau217 test results as a predictor of Alzheimer’s disease, accuracy rose from 75.5% using standard clinical evaluation alone to 94.5% accuracy after incorporating p-tau217 blood test results.

For those who like more detailed numbers:

• Confidence levels: neurologists’ average diagnostic confidence increased from 6.90 ± 1.74 to 8.49 ± 1.68 on a 10-point scale after seeing the biomarker data.
• Clinical findings: benefits were seen in both general neurology clinics and specialized memory units, and across all stages—subjective cognitive complaints (38.5%), mild cognitive impairment (47.5%), and dementia (14%).
• Agreement stats: pre-biomarker diagnoses matched final diagnoses in 71 of 200 cases (75.5%, kappa = 0.576), while post-biomarker diagnoses matched in 189 of 200 cases (94.5%, kappa = 0.906).

About that “kappa”: this is about Cohen’s kappa coefficient, a statistical measure of agreement. And in this case…

• Pre-biomarker diagnosis: kappa = 0.576, which indicates moderate agreement.
• Post-biomarker diagnosis: kappa = 0.906, which indicates almost perfect agreement.

So in other words, after adding the p-tau217 blood test, doctors’ diagnoses didn’t just improve in percentage accuracy, they also aligned much more strongly with the final confirmed diagnosis, far beyond what would be expected by chance.

And as for how much difference all this makes in real-world terms, 51 out of 200 patients had their diagnostic category changed after clinicians reviewed the p-tau217 results, correcting both false positives and missed Alzheimer’s cases.

In summary, a simple blood test for p-tau217 can provide a more accessible, less invasive alternative to expensive brain scans or deeply unpleasant spinal taps, improving early and accurate Alzheimer’s diagnosis and with it, improving people’s chances of getting a head start on managing the condition.

You can read the paper in full, here: Impact of blood p-tau217 testing on diagnosis and diagnostic confidence in cognitive disorders: a real-world clinical study

Want something more accessible than the latest blood tests?

People often forget and/or get confused about what the signs and symptoms of Alzheimer’s are, especially when it comes to forgetting and/or getting confused.

For example, dementia-related memory loss is less “where did I put my car keys?”, and more“what is this thing for?” (it’s your car keys). Or at a less advanced stage: “whose are these car keys?” (they are yours).

To learn more about this sort of distinction, see:

Is It Dementia? Spot The Signs (Because None Of Us Are Immune) ← If you’d like an objective test of memory and other cognitive impairments, this article also has a link to the industry’s gold standard test (it’s free)

(The Self-Administered Gerocognitive Exam (SAGE) is designed to detect early signs of cognitive, memory or thinking impairments)

Want to learn more?

For a much more in-depth coverage of the topic of Alzheimer’s treatment on the level of the personal rather than the molecular, you might like this excellent book we reviewed a while back:

The Spectrum of Hope: An Optimistic and New Approach to Alzheimer’s Disease and Other Dementias – by Dr. Gayatri Devi

…and if you just want to reduce your risk, then check out:

• Alzheimer’s Causative Factors To Avoid
• How To Reduce Your Alzheimer’s Risk

Take care!