The SPEAR UltraDetect™ pTau 231 biomarker assay kit

The SPEAR UltraDetect™ pTau231 biomarker assay kit is designed for Alzheimer’s disease research using plasma samples.

It must be used in combination with the SPEAR UltraDetect™ Reaction Kit and is intended for research use only.

A blood biomarker of early-stage amyloid pathology

pTau231, also called phosphorylated tau at threonine 231, is a blood-based biomarker that indicates any changes in tau phosphorylation in early stages, a condition that is associated with amyloid-β pathology. Its levels correlate with brain amyloid status, which is assessed by PET scans and cerebrospinal fluid (CSF) analysis.

As pTau 231 is one of the earliest tau epitopes to phosphorylate in Alzheimer’s disease (AD), it shows promise for the detection of preclinical Alzheimer’s. Scientists use pTau 231 to study the chronological relationship between amyloid and tau pathology. It is also used to diagnose the disease in early stages and assess risks.

Unparalleled sensitivity with SPEAR UltraDetect pTau 231

The SPEAR UltraDetect pTau 231 assay has unprecedented sensitivity and quantifiability, making it ideal for investigating pTau 231 as an early marker in longitudinal studies and future clinical trials.

SPEAR UltraDetect quantified 100 % of samples, including amyloid negative samples, with an average CV of 5 %, in a research comparing a cohort of PET-confirmed amyloid positive and amyloid negative patient samples.

EDTA Plasma samples (n=40) of AD and non-AD patient samples were measured on SPEAR UltraDetect pTau 231. SPEAR UltraDetect pTau 231 quantifies 100 % of AD and non-AD patient plasma samples [1 µL diluted sample]. Image Credit: Spear Bio

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Assay specifications

Source: Spear Bio

Scalable AD insights

Supporting Alzheimer’s disease research at any scale

Early tau phosphorylation changes linked to amyloid buildup and paired helical filament development are shown by the highly informative biomarker pTau231.

To track pathology in the central nervous system, pTau231 levels have been investigated alongside indicators such as pTau217 and neurofilament light. These levels are frequently raised in Alzheimer's disease (AD).

Conventional techniques for identifying phosphorylated tau, such as cerebrospinal fluid (CSF) analysis and conventional and digital ELISA kits, provide useful information, but they sometimes entail invasive collection, complex processing, and unreliable sensitivity.

The SPEAR UltraDetect™ pTau231 assay is a blood-based alternative that delivers exceptional analytical performance – without the limitations of traditional immunoassays. Researchers can use this assay to support:

• Multi-marker techniques (such as using neurofilament light or pTau271)
• Tracking changes in biomarkers in cohorts with early-stage or at-risk AD
• Therapeutic trial enrichment based on biomarker classification
• Translational research connecting blood-based and CSF biomarker trends

Across samples, across studies

Recommended for research across sample types and settings

The SPEAR UltraDetect^™ pTau231 assay is designed for Research Use Only (RUO) and is best used with plasma. Its sensitivity, specificity, and accuracy make it ideal for studies on pharmaceutical development pipelines and early-intervention research programs.

This assay enhances biomarker-driven decision-making in Alzheimer's research and facilitates investigations into the processes behind neurodegenerative diseases by providing extremely accurate, low-volume detection of pTau231.

Performance without tradeoffs

Designed for sensitivity and specificity without compromise

While preserving unmatched sensitivity at the attomolar level, SPEAR's wash-free, uniform technique reduces variability and complexity compared to conventional approaches that rely on CSF samples or surface-based formats.

By confirming each detection event through two separate molecular interactions, SPEAR's two-factor authentication technology lowers false positives and provides the high specificity required to interpret low-abundance signals with confidence.