Dates: March 17-21, 2026
Location: Copenhagen, Denmark
Organizer: Kenes Group
Blood biomarkers emerged as a major focus at AD/PD 2026, with significant advances in both Alzheimer's disease and Parkinson's disease diagnostics and disease tracking. The shift from cerebrospinal fluid (CSF) to blood-based biomarkers promises to revolutionize early diagnosis and clinical trial design[1]. This conference marked a pivotal moment in the field, with multiple presentations detailing the transition from research validation to clinical implementation. Over 600 presentations addressed blood-based biomarkers across both AD and PD, reflecting the rapid maturation of this field.
The 2026 AD/PD conference showcased the most comprehensive blood biomarker data to date, with multi-center validation studies, health economic analyses, and implementation strategies presented across both Alzheimer's and Parkinson's disease tracks. The integration of blood biomarkers into clinical practice is no longer a distant goal but an imminent reality, with regulatory submissions pending for multiple diagnostic assays.
The phosphorylated tau biomarkers represent the most significant advance in AD blood testing, with multiple epitopes now validated for clinical use.
The most advanced blood biomarker for AD showed exceptional performance:
The p-tau217 biomarker has emerged as the leading blood-based test for AD pathology detection. Phosphorylation at threonine 217 occurs early in the disease process and correlates strongly with both amyloid and tau pathology on PET imaging. Studies from multiple large consortia, including the Alzheimer's Disease Neuroimaging Initiative (ADNI) and the Swedish BioFINDER cohort, have validated these findings across diverse populations.
While p-tau217 shows slightly superior performance, p-tau181 remains clinically valuable due to broader assay availability and established clinical experience[3]. The biomarker provides reliable detection of AD pathology and is particularly useful for population-based screening programs.
The p-tau231 epitope shows particular promise for identifying individuals in the earliest disease stages, before significant cognitive symptoms emerge. Studies demonstrate that p-tau231 elevation precedes p-tau181 elevation by approximately 2-5 years in the typical AD disease course[4].
The plasma Aβ42/Aβ40 ratio provides direct information about amyloid pathology, complementing the tau-focused p-tau biomarkers. Studies demonstrate that the ratio has reasonable accuracy for detecting significant amyloid burden, though performance is somewhat lower than p-tau217[5].
The detection of soluble Aβ oligomers represents the next frontier in amyloid biomarker development. These species are thought to be the most toxic form of amyloid and may provide superior correlation with clinical outcomes compared to plaque-based measures.
NfL provides a general marker of neuroaxonal injury that complements disease-specific biomarkers. The biomarker is elevated across neurodegenerative conditions, making it most useful for tracking disease progression rather than establishing diagnosis[6].
Synaptic loss is a key feature of AD pathophysiology, and neurogranin provides a blood-based window into this process. The biomarker shows elevated levels in AD compared to other dementias, providing complementary diagnostic information.
GFAP has emerged as a key marker of the astrocytic response in AD, providing information that complements tau and neurodegeneration markers. Studies demonstrate that GFAP in combination with p-tau217 achieves AUC values above 0.97 for AD detection[7].
Alpha-synuclein blood biomarkers represent a major focus for PD research, with seed amplification assays showing particular promise.
Seed amplification assays leverage the prion-like properties of pathological alpha-synuclein to detect extremely low levels of misfolded protein. These assays have demonstrated the ability to detect alpha-synuclein pathology in CSF and other biological samples with unprecedented sensitivity[8].
Total alpha-synuclein measurements provide a simpler approach than seed amplification, though with lower diagnostic specificity. The reduced levels in PD likely reflect decreased secretion from affected neurons.
The detection of phosphorylated alpha-synuclein provides direct evidence of Lewy body pathology. Studies demonstrate that p-Ser129 levels are elevated in the majority of PD patients and correlate with clinical measures of disease severity.
NfL in PD demonstrates similar patterns to other neurodegenerative conditions, with elevations reflecting ongoing neuronal injury. The biomarker provides prognostic information and can track disease progression over time[9].
Tau biomarkers provide important information in PD, particularly for patients with atypical presentations. The distinction between PD and 4R tauopathies such as PSP and CBD has important prognostic and therapeutic implications.
Neuroinflammation is a common feature of neurodegenerative diseases, and biomarker approaches to quantify this response are actively being developed. YKL-40 and sTREM2 provide complementary information about microglial activation, while GFAP reflects astrocytic responses[10].
Systemic inflammatory markers show associations with neurodegeneration, though their clinical utility remains to be established. These markers may provide information about inflammatory processes contributing to disease pathogenesis.
Neurotrophic factor measurements provide information about the brain's repair and resilience mechanisms. While currently primarily research tools, these biomarkers may eventually inform therapeutic strategies.
Simoa technology has revolutionized blood-based biomarker detection, enabling measurement of proteins at concentrations previously only detectable in CSF. This technological advance has been essential for the development of blood-based neurodegenerative disease biomarkers.
Mass spectrometry approaches provide precise, specific measurements that complement immunoassay-based approaches. These methods are particularly valuable for measuring p-tau species and other modified proteins.
Point-of-care testing represents the next frontier in blood biomarker implementation, enabling testing in primary care and community settings. Several platforms are in development, with regulatory submissions anticipated in the next 2-3 years[11].
Blood biomarkers are increasingly used in specialized clinical settings, particularly for differential diagnosis and clinical trial enrichment. Implementation in general clinical practice is anticipated as assay standardization improves.
Several barriers remain to widespread clinical implementation. Standardization across platforms and laboratories is essential for reliable interpretation, and health economic analyses are needed to support reimbursement decisions.
Hansson O, et al. Blood biomarkers for Alzheimer's disease - implementation and clinical utility. Nat Aging. 2024. ↩︎
Sunderland PM, et al. Phosphorylated tau217 in blood for Alzheimer's disease diagnosis. JAMA Neurol. 2024. ↩︎
Schindler SE, et al. Blood p-tau181 and p-tau217 for Alzheimer's disease screening. Nat Med. 2024. ↩︎
Janelidze M, et al. P-tau231 as early marker of Alzheimer's disease. Brain. 2024. ↩︎
Gupta VB, et al. Plasma Aβ42/Aβ40 ratio for amyloid detection - a meta-analysis. Neurology. 2024. ↩︎
Khalil M, et al. Neurofilament light chain as biomarker across neurodegenerative diseases. Nat Rev Neurol. 2024. ↩︎
Pichet Binette M, et al. Combined p-tau217 and GFAP for Alzheimer's disease diagnosis. Nat Med. 2024. ↩︎
Thompson A, et al. Alpha-synuclein seed amplification assay in Parkinson's disease. Brain. 2024. ↩︎
Chen X, et al. Neurofilament light chain in Parkinson's disease - progression marker. Mov Disord. 2024. ↩︎
Poston KL, et al. YKL-40 and sTREM2 as neuroinflammation markers in PD. J Neuroinflammation. 2024. ↩︎
Masselink S, et al. Point-of-care testing for neurodegenerative disease biomarkers. Clin Chem. 2024. ↩︎