The new P-tau 217 test is almost here

[Julie G]

We've had quite a bit of chatter on the site lately about the new blood tests for AD pathology. The new p-Tau 217 test (used in PrecivityAD2, $1,250) appears to have the strongest correlation with a PET scan and/or CSF biomarkers of AD pathology.

Dr. Bredesen will be offering this direct-to-consumer by partnering with NeuroCode. The new test, called BRAINSCAN will be comprised of the triad p-Tau 217, NfL and GFAP. (Individual scores will be provided for each test, along with an interpretative report.) The introductory pricing will be around 50% of the PrecivityAD2 testing and will likely increase somewhat after the first month. You can sign up now to learn more about it and to be notified when it will be available. See BRAINSCAN.

[squirrel320]

Thanks so much Julie!

[NF52]

The new p-Tau 217 test (used in Precivity, $1,250) appears to have the strongest correlation with a PET scan and/or CSF biomarkers of AD pathology... The introductory pricing will be around 50% of the Precivity testing and will likely increase somewhat after the first month. You can sign up now to learn more about it and to be notified when it will be available.

Julie, just to clarify for our members, the Neurocode test is not the same test used in PrecivityAD™ or the newer PrecivityAD2™, which appears to be closest to the Neurocode . According to the website,

PrecivityAD® test identifies whether a patient is likely to have the presence or absence of amyloid plaques in the brain, a pathological hallmark of Alzheimer’s disease. The test relies on precise and robust quantitation of Amyloid Beta 42/40 ratio (Aβ 42/40) and detection of Apolipoprotein E proteotype (equivalent to ApoE genotype) in blood samples, using C₂N’s proprietary mass spectrometry platform...PrecivityAD2™ [is a] clinically-validated algorithm using a single cutoff that combines both Aβ42/40 and p-tau217/np-tau217 (%p-tau217) ratios [with] 88% sensitivity, 89% specificity [and] 0.94 AUC-ROC

https://precivityad.com/about-precivityad2-hcp-1-1-1

Per the Neurocode website, it looks like they use the well-researched ALZpath Dx: Plasma Phosphorylated Tau 217 (p-Tau 217), which was used by the Wisconsin Registry for Alzheimer's Prevention in a recently published study: Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology

Since the average age of the participants in that study was 66, with a standard deviation of +/- 9 years, do you know if Apollo Health is going to be advising people younger than age 55 that the likelihood of a positive prediction of elevated amyloid has not been well-documented in that age group? For reference, the AHEAD study has a lower age cutoff for screening of 55, and as squirrel320 found, it's possible to have Apoe 4/4 and be in your mid-to late 50's without even "intermediate" amyloid above 20 centiloids.

[Julie G]

Julie, just to clarify for our members, the Neurocode test is not the same test used in PrecivityAD™ or the newer PrecivityAD2™, which appears to be closest to the Neurocode

Absolutely- two completely different tests. The only reason that I mentioned it is because it's the only commercially available version of p-Tau 217 that I'm familiar with. Do you know if there are others?

Since the average age of the participants in that study was 66, with a standard deviation of +/- 9 years, do you know if Apollo Health is going to be advising people younger than age 55 that the likelihood of a positive prediction of elevated amyloid has not been well-documented in that age group? For reference, the AHEAD study has a lower age cutoff for screening of 55, and as squirrel320 found, it's possible to have Apoe 4/4 and be in your mid-to late 50's without even "intermediate" amyloid above 20 centiloids.

Great question. I could be mistaken as amyloid aggregation precedes tau accumulation, but the BRAINSCAN test largely ignores abeta and relies solely on p-Tau 217 instead along with NfL and GFAP. This test isn't meant to be used for diagnosis (as clearly stated on the website) but rather an assessment to gather information about current brain pathology that can be annually tracked.

[NF52]

Great question. I could be mistaken as amyloid aggregation precedes tau accumulation, but the BRAINSCAN test largely ignores abeta and relies solely on p-Tau 217 instead along with NfL and GFAP. This test isn't meant to be used for diagnosis (as clearly stated on the website) but rather an assessment to gather information about current brain pathology that can be annually tracked.

Actually, while it is counterintuitive from the label, the p-tau 217 test is preferred over amyloid tests precisely because of the 93% correlation with a positive amyloid PET scan, as stated on the Neurocode site:

Plasma p-Tau 217 levels correlate well with amyloid and tau PET imaging and perform as well as tests using CSF. This ALZpath p-Tau 217 assay was highly accurate in identifying amyloid-PET positive patients (AUC=.932).

https://neurocode.com/test/alzpath-plas ... d-tau-217/

This is an explanation of why the AlzPath p-tau 217 test is not just a test for tau:

..high-performing p-tau blood test results exhibit a substantial increase in patients with AD, occurring concurrently with extracellular Aβ plaque deposition, an AD hallmark feature...Longitudinally, plasma p-tau217 values showed an annual increase only in Aβ-positive individuals, with the highest increase observed in those with tau positivity.....
Among proposed blood tau biomarkers, phosphorylated tau at threonine 217 (p-tau217) has consistently shown high performance in differentiating AD from other neurodegenerative disorders... Additionally, p-tau217 demonstrates a unique longitudinal trajectory, showing increases associated with worsening brain atrophy and declining cognitive performance in individuals with elevated Aβ pathology.

Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology This chart shows that in AD, an increase in plasma tau (purple line) correlates with an increase in abnormal amyloid (brown line) about 5 years earlier, with potentially 20 years or more before any clinical symptoms MAY happen.

Image.jpeg

https://alz-journals.onlinelibrary.wile ... alz.037518

But it may still be that it would be difficult to detect in people below age 50, even with ApoE 4/4.

[Julie G]

This is an explanation of why the AlzPath p-tau 217 test is not just a test for tau.

Yes! As I mentioned, it’s well known that amyloid precede tau. Your graph beautifully illustrates this.

But it may still be that it would be difficult to detect in people below age 50, even with ApoE 4/4.

Agree, we need more data. Younger people (even 4/4s) may not have enough accumulation for it to register. Although I suspect that with brain injuries at any age, NfL, GFAP, and even p-Tau-217 may be elevated (?)

[squirrel320]

Hello - I am curious if anyone has any additional information on Lucent's p-tau 217 test? It appears to be available through a physician's order? Not direct to consumer. Please see link?

https://www.lucentdiagnostics.com/about-lucentad/

[NF52]

Hello - I am curious if anyone has any additional information on Lucent's p-tau 217 test? It appears to be available through a physician's order? Not direct to consumer. Please see link?

https://www.lucentdiagnostics.com/about-lucentad/

Hi Sheri,

I'm not directly familiar with the Lucent AD p-Tau 217 test, but it does claim to have a 90% accuracy in predicting a positive Amyloid CSF test or PET scan. The link you provided notes that it

is intended for patients with mild cognitive impairment and/or who are undergoing cognitive evaluation. This test is new and is not currently covered by commercial insurance, Medicare or Medicaid.

Since you've mentioned living in Canada, you may want to check to see whether your health care would cover it, or your doctor would order it. From what I know of the p-tau 217 test, and the diagram I shared above in a post, this really is used as a predictor of a positive amyloid test, and does NOT necessarily signal that you have an observable PET- scan level of tau tangles in any area of your brain. Since you are going to receive the results of the Amyloid PET scan in the AHEAD screening within a few weeks (hopefully!), paying for this test may not tell you anything new. I'm a member of a research participant advisory board that is advocating (as are other participants and patients) for more transparency around results of tau and other biomarkers to participants--especially since doing so does not interfere with the "blind" assignment to placebo or drug.

Keep us posted if you decide to pursue this!

Nancy

[DDorans]

This may be a stupid question but why would I want to have this test. I’m a 4/4 so I would think most likely not have good results. When I found out I was a 4/4 I was very stressed for a while but then came to terms with it and realized it was good to know so I could do the right things using a lot of the Bredeson protocol. I would feel that I would be wondering when my amyloid would create tau. Very curious about other peoples take on this subject.

[barbS]

This may be a stupid question but why would I want to have this test. I’m a 4/4 so I would think most likely not have good results. When I found out I was a 4/4 I was very stressed for a while but then came to terms with it and realized it was good to know so I could do the right things using a lot of the Bredeson protocol. I would feel that I would be wondering when my amyloid would create tau. Very curious about other peoples take on this subject.

I appreciate the when and I am diligently working on the why. LOL. In a way. Many of the replies I find in the forum are beyond what I can easily understand which frustrates me even more. I find one research that undoes a recent find and on and on.

Right now I am in the: https://healthsciences.arizona.edu/news ... alzheimers taking a look around.
"“We believe that altered lipid turnover significantly contributes to neurodegenerative diseases, just as it does to metabolic and cardiovascular diseases."

Fei Yin, PhD

*spoiler: no conclusions due to "mights" in the article

I hope when a marker? test does become available - I hope it is reasonable for retired folks, with limited funds, to use credit to pay for--small personal loan? The supplements are beccoming a bit of a financial hurdle - since really clean food, water filters, air filters, etc figure into the apoe3/4 scenario, and I feel are most crucial to the "thing".

Just a teeny rant but so happy I found my daughter has no apoe 3/4 or 4/4 to be found. blessings to all