A new blood test that measures MTBR-tau243, a tau protein fragment associated with Alzheimer’s disease (AD), is poised to revolutionize the way clinicians diagnose and stage the condition. Developed by researchers at Washington University in St. Louis and Lund University in Sweden, the test enables a noninvasive, accessible method for assessing tau pathology — a central feature of AD.
MTBR-tau243 originates from the microtubule-binding region of tau and is strongly linked to tau tangles in the brain. In clinical studies involving the Swedish BioFINDER-2 and Knight Alzheimer cohorts, plasma levels of MTBR-tau243 rose progressively with advancing AD, closely mirroring tau PET imaging results. This strong correlation underscores its value as a proxy for neuroimaging and positions it as a practical alternative in everyday clinical care.
Current gold standards for tau detection — cerebrospinal fluid analysis and PET imaging — are effective but invasive, costly, and not easily scalable. A blood-based biomarker like MTBR-tau243 offers a more feasible option for broad clinical use. Importantly, it works synergistically with other markers, such as p-tau217. When both are elevated, the likelihood of AD being the cause of cognitive symptoms increases significantly.
Beyond diagnosis, MTBR-tau243 could help clinicians tailor treatment. Early-stage AD, with limited tau pathology, may respond best to anti-amyloid therapies, while late-stage disease, characterized by extensive tau accumulation, might benefit from anti-tau strategies. Accurate staging through a simple blood draw could guide therapy choice and timing.
Despite its promise, the test has limitations: it requires a larger blood volume than most assays and performs best in moderate-to-advanced stages. Further standardization across diverse populations and clinical environments is essential before widespread adoption. Additionally, while informative, blood tests lack the spatial detail offered by neuroimaging and may be best used as complementary tools.
Expected to be available soon through C2N Diagnostics, this test could shift Alzheimer’s care toward more personalized, biomarker-driven decision-making — improving early detection, treatment planning, and monitoring of disease progression.