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Differences in Alzheimer's disease blood biomarker stability: Implications for the use of tau/amyloid ratios
Figdore DJ, Schuder BJ, Ashrafzadeh-Kian S, Gronquist T, Bornhorst JA, Algeciras-Schimnich A.. Alzheimer's & dementia : the journal of the Alzheimer's Association, 2025-04-01
Topic: Amyloid, tau and blood-test diagnosis
Introduction We compare the stability of phosphorylated tau (p-tau)217, amyloid beta (Aβ)42, Aβ40, Aβ42/40, and p-tau217/Aβ42 at different storage temperatures. Methods Ten ethylenediaminetetraacetic acid-plasma sample aliquots stored at frozen, refrigerated, and ambient temperatures were tested at various timepoints up to 30 days. The mean percent change from baseline was calculated. Results Aβ42 and Aβ40 concentrations decreased by >15% after 6 hours at ambient temperature and after 24 hours refrigerated, while p-tau217 remained stable over 72 hours with < 10% deviation from baseline at either storage temperature. The Aβ42/40 ratio remained relatively constant as each analyte concentration decreased concurrently, while the p-tau217/Aβ42 ratio deviated from baseline over time. All biomarkers were stable up to 30 days frozen. Discussion Differences in the stability of Aβ42 and p-tau217 may lead to altered p-tau217/Aβ42 ratio results if samples are not handled properly during the pre-analytical testing phase. Ideally, samples should be frozen promptly and sent to the laboratory frozen. Highlights Plasma phosphorylated tau (p-tau)217, amyloid beta (Aβ)42, Aβ40, Aβ42/40, and p-tau217/Aβ42 stability was assessed. P-tau217 was stable, but Aβ42 and Aβ40 started decreasing by 6 hours at ambient temperature. The analyte stability differences led to falsely increased p-tau217/Aβ42 ratios. Increases > 15% were seen in p-tau217/Aβ42 after 6 hours at ambient temperature or 24 hours at 4°C.
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APA 7th
Figdore, D. J., Schuder, B. J., Ashrafzadeh-Kian, S., Gronquist, T., Bornhorst, J. A., & Algeciras-Schimnich, A. (2025). Differences in Alzheimer's disease blood biomarker stability: Implications for the use of tau/amyloid ratios. Alzheimer's & dementia : the journal of the Alzheimer's Association. https://doi.org/10.1002/alz.70173
Vancouver
Figdore DJ, Schuder BJ, Ashrafzadeh-Kian S, Gronquist T, Bornhorst JA, Algeciras-Schimnich A. Differences in Alzheimer's disease blood biomarker stability: Implications for the use of tau/amyloid ratios. Alzheimer's & dementia : the journal of the Alzheimer's Association. 2025. doi:10.1002/alz.70173. PMID: 40308118.
BibTeX
@article{figdore2025-40308118,
author = {Figdore, D. J. and Schuder, B. J. and Ashrafzadeh-Kian, S. and Gronquist, T. and Bornhorst, J. A. and Algeciras-Schimnich, A.},
title = {{Differences in Alzheimer's disease blood biomarker stability: Implications for the use of tau/amyloid ratios}},
journal = {Alzheimer's \& dementia : the journal of the Alzheimer's Association},
year = {2025},
doi = {10.1002/alz.70173},
pmid = {40308118},
url = {https://doi.org/10.1002/alz.70173}
}
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Key findings
- Results Aβ42 and Aβ40 concentrations decreased by >15% after 6 hours at ambient temperature and after 24 hours refrigerated, while p-tau217 remained stable over 72 hours with < 10% deviation from baseline at either storage temperature.
- Discussion Differences in the stability of Aβ42 and p-tau217 may lead to altered p-tau217/Aβ42 ratio results if samples are not handled properly during the pre-analytical testing phase.
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Study details
- Evidence strengthLow
How this study scored 48/100
Published in a leading specialty journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 28 of the 58 points we could judge it on, which is 48 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Alzheimer's & dementia : the journal of the Alzheimer's Association) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 40308118) |
| Free to read | 2 / 2 | Free to read |
| Points | 28 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 28 of the 58 points we could judge it on is 48 out of 100. |
| Total | 48 / 100 | — |
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