SPEAR UltraDetect™ pTau 231 Biomarker Assay Kit
The SPEAR UltraDetect™ pTau 231 biomarker assay kit is highly sensitive and ideal for Alzheimer’s research using plasma samples. Requires SPEAR UltraDetect™ Reaction Kit. For research use only.
Oliver Tassinari, VP, Business Development & Sales, Spear Bio introduces new assays for Alzheimer’s disease clinical research
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A blood biomarker of early-stage amyloid pathology
pTau231 (phosphorylated tau at threonine 231) is a blood-based biomarker that reflects early tau phosphorylation changes associated with amyloid-β pathology. It correlates with brain amyloid status as measured by PET and CSF. pTau 231 is one of the earliest tau epitopes to phosphorylate in Alzheimer’s disease suggesting strong potential for detecting preclinical Alzheimer’s disease. pTau 231 is used in research for early disease detection, risk stratification, and to study the temporal sequence of amyloid and tau pathology.
Unparalleled Sensitivity with SPEAR UltraDetect pTau 231
The SPEAR UltraDetect pTau 231 assay demonstrates unparalleled sensitivity, delivering high quantifiability – important for exploration of pTau 231 as an early marker in longitudinal studies and potential applications in clinical trials.
In a study comparing a cohort of PET-confirmed amyloid positive and amyloid negative patient samples, SPEAR UltraDetect quantified 100% of samples – including amyloid negative samples with average CV of 5%.
Unlocking the potential of pTau 231 in Alzheimer’s disease research with the enhanced sensitivity and precision of the SPEAR UltraDetect pTau 231 Assay
Phosphorylated tau at threonine 231 (pTau 231) is emerging as a promising blood-based biomarker for incipient Alzheimer’s disease (AD) pathology, yet the sensitivity of existing assays like Simoa® is still inadequate to reliably quantify blood pTau 231 in healthy individuals, with reported 78% and 40% detectability and quantifiability, respectively.
In this application note, we compare the analytical performance of SPEAR UltraDetect™ pTau 231 Assay with Simoa pTau 213 Advantage PLUS Assay in measuring plasma pTau 231. The SPEAR assay demonstrates higher sensitivity and precision, achieving 100% detection and 100% quantification in healthy individuals and greater precision (Average CV 4.2% vs. 13.8% for Simoa). With enhanced sensitivity and precision, SPEAR UltraDetect enables robust quantification of baseline and subthreshold changes in pTau 231 levels, unlocking the potential of pTau 231 as a plasma biomarker for early AD detection and longitudinal tracking of disease progression.
Resource details:
- Resource type: Application note
- Page count: 4 pages
- Read time: 6 mins
SPEAR UltraDetect brochure
SPEAR UltraDetect™ is an ultra-sensitive, homogeneous immunoassay platform designed for reliable detection of low-abundance protein biomarkers. Powered by SPEAR’s unique two-factor authentication mechanism and standard qPCR readout, UltraDetect assays deliver exceptional sensitivity, specificity, and precision in a fully wash-free workflow using as little as 1 µL of sample. The solution enables robust biomarker quantification for neurological and clinical research applications with simplified workflows and broad instrument compatibility.
Download this brochure to discover the fundamentals of SPEAR Technology, key features of SPEAR UltraDetect Assays, and a comprehensive summary of the complete SPEAR Solution.
Resource details:
Resource type: Brochure
Page count: 4 pages
Read time: 6 minutes
Enhanced early Alzheimer's detection via ultra‑sensitive plasma pTau 217 measurement
Friday, January 30 at 15:00 GMT | 16:00 CET | 10:00 EST | 07:00 PST
Growing evidence shows that plasma phosphorylated tau (pTau) 217 is one of the most accurate and reliable blood-based biomarkers for identifying early Alzheimer’s disease pathology, even before the onset of clinical symptoms. As research efforts expand beyond cerebrospinal fluid (CSF) biomarkers and PET imaging, sensitive and specific plasma assays have become essential for improving early detection, supporting clinical trial design, and enabling large‑scale population screening.
In this SelectScience webinar, Dr. Nicholas Ashton of Banner Health and Dr. Laurel Provencher of Spear Bio will explore how emerging analytical innovations enhance the measurement of low-abundance plasma pTau 217, helping researchers better classify amyloid positivity, improve disease discrimination, and align blood-based results with established CSF biomarker profiles.
The webinar will compare assay performance across the BioFINDER and WRAP cohorts – two leading longitudinal studies shaping our understanding of Alzheimer’s progression. It will also highlight how the SPEAR UltraDetect™ platform from Spear Bio is designed to deliver the ultra‑sensitive, high‑specificity detection capabilities needed to support these advancements in blood-based Alzheimer’s research.
Certificate of attendance
If you attend the live webinar, you will automatically receive a certificate of attendance, including a learning outcomes summary, for continuing education purposes. If you view the on-demand webinar, you can request a certificate of attendance by emailing editor@selectscience.net.
Webinar details
- Cost: Free to attend
- Location: Online
- Duration: 60 minutes
Registration is required to secure your place. If you register but can’t attend live, you will receive a link to the on‑demand recording once it becomes available.
Spear Bio expands Alzheimer’s biomarker portfolio with novel epTau 217 and eMTBR-Tau assays, supported by a fully automated workflow
At the 2026 Alzheimer’s Association International Conference® (AAIC 2026), Spear Bio showcased the launch of two novel blood-based biomarker assays — SPEAR epTau 217 and SPEAR eMTBR-Tau — alongside its fully automated S.W.I.F.T. workflow solution for hands-free processing of SPEAR UltraDetect™ and TrueDetect™ platforms.
These two new assays expand the company’s Alzheimer’s disease (AD) biomarker portfolio by enabling measurement of distinct aspects of Tau biology, while the automated workflow provides a scalable solution for reproducible, high-throughput clinical research.
In the video, Oliver Tassinari, VP of Business Development & Sales at Spear Bio, discusses the company’s commitment to delivering innovative, reliable immunoassays that enable researchers to generate high-quality biomarker data with minimal workflow complexity.
The SPEAR epTau 217 assay measures a unique subset of phosphorylated Tau 217 and was shown at AAIC to be the only Tau biomarker evaluated that produced highly consistent measurements between paired venous and capillary blood samples, unlike conventional plasma Tau biomarkers that exhibited an upward bias in capillary blood. While the biological basis of this observation remains under investigation, these findings suggest that epTau 217 may provide a more robust blood-based signal for decentralized sample collection and Alzheimer’s disease screening applications.
Spear Bio also introduced the first immunoassay for plasma eMTBR-Tau, an emerging biomarker that specifically reflects Tau tangle pathology. Data presented at the meeting demonstrated strong assay performance and showed marked increases in plasma eMTBR-Tau in individuals with advanced Alzheimer’s disease, addressing an important need for a blood-based Core 2 biomarker for AD Tau pathology.
The video also features insights from Dr. Thomas Karikari, Director of the Biomarker and Neurogenetics Core at the University of Pittsburgh Alzheimer’s Disease Research Center. Karikari explains why Alzheimer’s disease research requires a multi-biomarker approach to capture the complex biology of the disease, including amyloid pathology, Tau pathology, neurodegeneration, and inflammation. He discusses the growing importance of blood-based biomarkers that reflect Tau tangle pathology, highlighting the potential of emerging assays such as eMTBR-Tau to support disease staging, improve understanding of disease progression, and complement established measures including Tau PET imaging and neuropathological assessment.
Interview filmed at the 2026 Alzheimer's Association International Conference® (AAIC 2026).
Exploratory biomarker discovery driven by ultra-sensitive assays
Yao Chen of Sanofi shares how her team achieves sensitivity, specificity, precision, and robustness in protein biomarker detection
