Are blood-based biomarkers accurate in detecting Alzheimer’s disease?
Näytönastekatsaukset
8.4.2026
Level of evidence: C
In cognitively impaired individuals evaluated in specialized care settings, blood-based biomarkers (Aβ42/Aβ40, p-tau217, %p-tau217, p-tau181, and p-tau231) might have clinically meaningful diagnostic accuracy for detecting Alzheimer’s disease pathology when compared with amyloid PET, cerebrospinal fluid biomarkers, or neuropathology. The highest and most consistent diagnostic performance is observed for p-tau217 and %p-tau217.
The certainty of the evidence is limited by risk of bias and heterogeneity across studies and assay platforms; therefore, blood-based biomarkers should be interpreted in conjunction with clinical assessment and assay-specific characteristics.
| Reference | Study type | Population | Intervention and comparison | Outcomes | Risk of bias [Table «Additional comments for included studies»2. Additional comments] |
|---|---|---|---|---|---|
| SR=systematic review; MA=meta-analysis | |||||
| «Pahlke S, Kahale LA, Mahinrad S, et al. Blood-based biomarkers for detecting Alzheimer's disease pathology in cognitively impaired individuals within specialized care settings: A systematic review and»1 | SR/MA | Cognitively impaired individuals (mild cognitive impairment or dementia) evaluated in specialized care settings (memory clinics, tertiary/specialty care). A total of 49 observational studies were included. | Intervention: Blood-based biomarkers Aβ42/Aβ40, p-tau217, %p-tau217, p-tau181, and p-tau231 measured using immunoassays or mass spectrometry. Comparison: Reference standards consisting of amyloid PET, cerebrospinal fluid Alzheimer's disease biomarkers, or neuropathology | Diagnostic test accuracy outcomes including sensitivity and specificity | Low |
| Reference | Comments |
|---|---|
| «Pahlke S, Kahale LA, Mahinrad S, et al. Blood-based biomarkers for detecting Alzheimer's disease pathology in cognitively impaired individuals within specialized care settings: A systematic review and»1 | Mean age ranged from 62.6 to 85.9 years; both sexes represented. Studies were conducted in Europe, North America, and Asia. There were risk of bias in almost all studies, including due to patient selection, index test, reference standard, and flow and timing. The fold change between biomarker concentrations in amyloid-positive versus amyloid-negative individuals, and this was not accounted for. |
Results
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Absolute number of events (%) I | Absolute number of events (%) C | Pooled effect range |
|---|---|---|---|---|---|
| Level of evidence: low The quality of evidence is downgraded due to various study limitations and imprecision I= intervention; C=comparison; | |||||
| Aβ42/Aβ40 | Up to 11 assays across multiple studies (total n ≈ several thousand) | Cross-sectional | NR | NR | sensitivity 59–90 % specificity 61–83% |
| p-tau217 | Up to 7 assay platforms across multiple studies | Cross-sectional | NR | NR | sensitivity 49–91 % specificity 75–97% |
| %p-tau217 | 2 assay platforms (IP-MS based), multiple studies | Cross-sectional | NR | NR | sensitivity 89–91% specificity 86–92% |
| p-tau181 | 48 assay platforms across multiple studies) | Cross-sectional | NR | NR | sensitivity 67–86% specificity 68–89% |
| p-tau231 | Single assay platform (multiple studies) | Cross-sectional | NR | NR | sensitivity 82% specificity 82% |
References
- Pahlke S, Kahale LA, Mahinrad S, et al. Blood-based biomarkers for detecting Alzheimer's disease pathology in cognitively impaired individuals within specialized care settings: A systematic review and meta-analysis. Alzheimers Dement 2025;21(11):e70828 «PMID: 41193403»PubMed