New Immunoassay Enables Ultrasensitive Blood-Based Tau Tangle Measurement

Alamar Biosciences (Fremont, CA, USA) has introduced the first commercial immunoassay for enhanced microtubule binding region tau (eMTBR-Tau). The assay is available within the NULISAseq Neuro 220 multiplexed panel kits for immediate use on the ARGO HT automated platform and as a single-plex assay through the company’s Technology Access Program. The launch was announced on July 7, 2026, with availability stated as immediate.

The assay quantifies eMTBR-Tau in plasma, a biomarker that specifically reflects tau tangle pathology and has shown strong associations with cognitive decline, clinical staging, and therapeutic response monitoring in Alzheimer’s disease research. The NULISA platform targets the microtubule binding region fragment (MTBR) generated by endogenous cleavage at site 256, enabling tangle-specific measurement. The assay achieves attomolar sensitivity while multiplexing eMTBR-Tau with additional neurodegeneration and neuroinflammation biomarkers from a single low-volume specimen.

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Blood testing has historically offered pTau‑217 as an amyloid indicator, but a positive result alone is insufficient for a confirmatory diagnosis because many individuals with amyloid accumulation have not yet developed tau tangles. Consequently, quantifying tau tangle burden has relied on positron emission tomography, which is resource-intensive. Recent studies have shown that a blood-based eMTBR‑tau243 mass spectrometry assay correlates strongly with tau tangle burden, supporting eMTBR‑Tau as a promising blood-based surrogate for tau positron emission tomography. 

Alamar is presenting eMTBR‑Tau data at the Alzheimer’s Association International Conference 2026 workshop in London, including analytical performance, correlation with tau positron emission tomography, and patient stratification across Alzheimer’s disease stages. The NULISAseq Neuro 220 Panel with eMTBR‑Tau is available now, with single‑plex access offered through the Technology Access Program.

“eMTBR-Tau is emerging as one of the most important biomarkers in Alzheimer's disease. We believe the ability to measure tangle-specific tau pathology in combination with other neurodegeneration and neuroinflammation biomarkers from blood, with the sensitivity and specificity that NULISA™ provides, will open new possibilities in clinical research and clinical trials for disease staging, patient stratification, therapy response monitoring and, ultimately, for precision medicine,” said Dr. Yuling Luo, founder, chief executive officer and chair of Alamar Biosciences.

“eMTBR-Tau is a vital addition to the blood-based biomarker toolkit. The ability to easily measure tau tangle pathology from a blood draw enables better disease classification and staging and has the potential to be transformative to advancing the development of new therapies for the treatment of Alzheimer’s disease,” said Dr. Nicholas Ashton, senior director of the Fluid Biomarker Laboratory at Banner Health. 

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