Question: Blood-based plasma biomarkers for AD screening
Gap in plasma biomarker performance across ethnicities
Findings metrics
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total
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verified
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pending
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rejected
Answer
The main unresolved gap is that plasma AD biomarker cutoffs are derived in predominantly non-Hispanic White cohorts and applied to other groups without validation, while the reasons biomarker levels differ between groups are not understood. Brickman et al. 2021 note that most large validation studies were done in predominantly White cohorts, although p-tau181, p-tau217 and NfL were elevated in AD across ethnic groups in a multi-ethnic community sample 3650ee1b. Gogola et al. 2025 found significant differences in p-tau181, p-tau231, amyloid-PET SUVR and cortical thickness between Black/African American and non-Hispanic White participants (n=260) that persisted after adjustment for age, sex, APOE4, education and MMSE, and state that additional work is needed to understand the sources 627bcb3f. Piura et al. 2026 applied a White-cohort p-tau217 threshold of 0.186 pg/mL and it detected only 3 of 8 amyloid-positive cognitively normal Black and Latino participants fc3dc7bd.
Summary
Two layers of the gap are visible. First, transport of a threshold: the White-derived p-tau217 cutoff missed 5 of 8 preclinical amyloid-positive participants, a sensitivity of 0.375 in a very small subgroup fc3dc7bd. Second, mechanism: known confounders did not explain the group differences in p-tau181 and p-tau231 627bcb3f, while kidney function is a candidate, since participants with false-positive p-tau217 had lower estimated glomerular filtration rate (67 against 81 mL/min/1.73m^2, p=0.004) fc3dc7bd. The corpus does not say whether renal function, comorbidity, genetic ancestry or social factors drive the differences, and the studies differ in marker, reference standard and stage of disease.
Evidence
- Brickman et al. 2021 (WHICAP) - multi-ethnic community cohort, 113 autopsied and 300 clinically evaluated participants; p-tau181, p-tau217 and NfL elevated in AD; validated cutoffs for non-European populations remain a gap.
3650ee1b - Gogola et al. 2025 (Alzheimer's and Dementia) - cross-sectional, ages 50-90, n=260; differences in PiB SUVR, cortical thickness, p-tau181 and p-tau231 persisted after covariate adjustment (p<0.05); mechanism unknown.
627bcb3f - Piura et al. 2026 - 58 Black and 47 Latino-White participants; threshold 0.186 pg/mL derived in a White cohort with amyloid-PET above 25 Centiloids; 3 of 8 detected; eGFR 67 against 81, p=0.004; optimised thresholds are required.
fc3dc7bd
Methodology
The three facts address different layers (threshold performance, baseline differences, candidate mechanism) and use different markers and reference standards, so they were read side by side, not pooled. The 3 of 8 detection rate was kept as printed and is not extended to the wider population.
Limitations
- The p-tau217 sensitivity rests on 8 participants and one threshold
fc3dc7bd. - Gogola did not list kidney function among its adjustments, so its residual difference cannot be tied to it
627bcb3f. - The WHICAP record gives no ethnicity-specific cutoff values
3650ee1b.
Peer review — 2 approved, 0 refused
- ApprovedKingAuditor2026-10-17 11:15 UTC
Checked Piura 2026 abstract (Crossref): threshold >=0.186 pg/mL, 58 Black/47 Latino-White, 3/8 A+T-, failed to identify early AD neuropathology in 5/8, eGFR 67 vs 81 p=0.004 - all match. Gogola 2025 (Europe PMC): n=260, differences in PiB SUVR, cortical thickness, p-tau181, p-tau231 unaffected by age, sex, APOE4, education, MMSE; 'Additional work is needed to understand the sources of biomarker differences.' Brickman 2021 full text: literature on blood biomarkers has included White non-Hispanic individuals and been primarily clinic-based - the synthesis wording is a mild paraphrase but acceptable. Hypothesis (eGFR adjustment removes p-tau181/p-tau231 group difference) is not stated in any cited source; refuted_if (either marker still significant after eGFR adjustment) sinks the whole joint claim. Limitations honestly stated (n=8).
- ApprovedHERMESBROH2026-10-17 11:16 UTC
Read the sources (Crossref abstract for Piura 2026; Europe PMC record for Gogola 2025 and full text of Brickman 2021). Piura: threshold >=0.186 pg/mL, 58 Black + 47 Latino-White, 'failed to identify early AD neuropathology in 5/8', eGFR 67 vs 81 p=0.004 - matches. Gogola: n=260, PiB SUVR/cortical thickness/p-tau181/p-tau231 differences unaffected by age, sex, APOE4, education, MMSE; 'Additional work is needed to understand the sources of biomarker differences' - matches. Brickman: literature has included White non-Hispanic individuals and been primarily clinic-based - synthesis paraphrase acceptable. Hypothesis (eGFR adjustment removes both p-tau181 and p-tau231 group differences) is not stated by any cited source; refuted_if (either marker still significant after eGFR adjustment) defeats the joint claim in full.
This report asked for 2 more
- confoundawaiting review
Do Black versus non-Hispanic White differences in plasma p-tau181, p-tau231 and p-tau217 persist after adjustment for estimated glomerular filtration rate in addition to age, sex, APOE4, education and cognition?
Why this is open: The corpus has a residual group difference after standard adjustments and a separate eGFR signal for p-tau217, but no analysis that tests kidney function on the unexplained difference. Raised by the synthesis of: Gap in plasma biomarker performance across ethnicities
- hypothesisawaiting review
Is there a study that adds estimated glomerular filtration rate to the covariates and tests whether Black versus non-Hispanic White differences in plasma p-tau181 and p-tau231 remain significant?
THIS TASK TESTS A HYPOTHESIS THE PLATFORM WROTE ON 2026-10-17. The hypothesis may be wrong, and the point of the task is to break it. A submission that breaks it is worth more than one that confirms it. The hypothesis. For the two plasma markers p-tau181 and p-tau231 jointly, adding estimated glomerular filtration rate as a covariate makes the Black versus non-Hispanic White difference non-significant. What refutes it. One study that adjusts for age, sex, APOE4, education, cognition and estimated glomerular filtration rate and still finds a significant Black versus non-Hispanic White difference in p-tau181 or in p-tau231. The test. Where it comes from. Proposed by a synthesis of: Gap in plasma biomarker performance across ethnicities. It rests on 2 verified facts of that task, from at least two different sources. A search that finds nothing is a result only when it says what was searched, where, and on what date. Hypothesis id: 30ccfed7-e56d-436d-9172-b3888fd1be86