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A/T/N: An unbiased descriptive classification scheme for Alzheimer disease biomarkers
Jack CR, Bennett DA, Blennow K, Carrillo MC, Feldman HH, Frisoni GB, Frisoni GB, Hampel H et al.. Neurology, 2016-07-01
Topic: Amyloid, tau and blood-test diagnosis
Biomarkers have become an essential component of Alzheimer disease (AD) research and because of the pervasiveness of AD pathology in the elderly, the same biomarkers are used in cognitive aging research. A number of current issues suggest that an unbiased descriptive classification scheme for these biomarkers would be useful. We propose the "A/T/N" system in which 7 major AD biomarkers are divided into 3 binary categories based on the nature of the pathophysiology that each measures. "A" refers to the value of a β-amyloid biomarker (amyloid PET or CSF Aβ42); "T," the value of a tau biomarker (CSF phospho tau, or tau PET); and "N," biomarkers of neurodegeneration or neuronal injury ([(18)F]-fluorodeoxyglucose-PET, structural MRI, or CSF total tau). Each biomarker category is rated as positive or negative. An individual score might appear as A+/T+/N-, or A+/T-/N-, etc. The A/T/N system includes the new modality tau PET. It is agnostic to the temporal ordering of mechanisms underlying AD pathogenesis. It includes all individuals in any population regardless of the mix of biomarker findings and therefore is suited to population studies of cognitive aging. It does not specify disease labels and thus is not a diagnostic classification system. It is a descriptive system for categorizing multidomain biomarker findings at the individual person level in a format that is easy to understand and use. Given the present lack of consensus among AD specialists on terminology across the clinically normal to dementia spectrum, a biomarker classification scheme will have broadest acceptance if it is independent from any one clinically defined diagnostic scheme.
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APA 7th
Jack, C. R., Bennett, D. A., Blennow, K., Carrillo, M. C., Feldman, H. H., Frisoni, G. B., et al. (2016). A/T/N: An unbiased descriptive classification scheme for Alzheimer disease biomarkers. Neurology. https://doi.org/10.1212/wnl.0000000000002923
Vancouver
Jack CR, Bennett DA, Blennow K, Carrillo MC, Feldman HH, Frisoni GB, et al. A/T/N: An unbiased descriptive classification scheme for Alzheimer disease biomarkers. Neurology. 2016. doi:10.1212/wnl.0000000000002923. PMID: 27371494.
BibTeX
@article{jack2016-27371494,
author = {Jack, C. R. and Bennett, D. A. and Blennow, K. and Carrillo, M. C. and Feldman, H. H. and Frisoni, G. B. and Hampel, H. and others},
title = {{A/T/N: An unbiased descriptive classification scheme for Alzheimer disease biomarkers}},
journal = {Neurology},
year = {2016},
doi = {10.1212/wnl.0000000000002923},
pmid = {27371494},
url = {https://doi.org/10.1212/wnl.0000000000002923}
}
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Key findings
- A number of current issues suggest that an unbiased descriptive classification scheme for these biomarkers would be useful.
Why it matters
This 2016 paper proposes the "A/T/N" scheme, which sorts seven Alzheimer's biomarkers into three groups: A for amyloid (amyloid PET or CSF Aβ42), T for tau (CSF phospho-tau or tau PET) and N for neurodegeneration (FDG-PET, structural MRI or CSF total tau). Each group is rated positive or negative, giving profiles such as A+/T+/N−. The authors present it as a descriptive research shorthand that makes no assumption about which changes come first and is "not a diagnostic classification system"; it reports no patient data and is not about treatment.
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Study details
- Evidence strengthLow
How this study scored 64/100
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.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | 4 / 4 | Neurology: journal h-index 525 (OpenAlex, 2026-10-29) |
| 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 | 1 / 5 | 2016 — within 20 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 / 7 | Cited 1,861 times (OpenAlex, 2026-10-10) |
| Citations per year | 5 / 5 | 155.1 citations a year over 12 year(s) since 2016 |
| Impact for its field and year | 6 / 6 | Cited 85.0× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 5 / 6 | Cited by 157 other studies in this library |
| Still being cited | 4 / 4 | Cited 665 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Bruno Dubois: h-index 147 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | Mayo Clinic: institution h-index 1,606 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 4 institution(s) in 2 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 27371494) |
| Free to read | 2 / 2 | Free to read |
| Total | 64 / 100 | — |
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Read the original
- DOI: 10.1212/wnl.0000000000002923
- PubMed: 27371494
- Original source →
- Free full text: PubMed Central →
Full text: free to read — PubMed Central lists this copy as free to read: the link above (checked 10 Oct 2026).
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