A biomarker is a measurable indicator of some biological condition; often measured using blood, urine, or soft tissues.
One biomarker has changed the landscape of Alzheimer’s research. Because of this we have a substantial window of time in which we may be able to intervene in the progression of Alzheimer’s. In 2025 the first blood test for Alzheimer’s disease, the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio, was cleared by the U.S. Food and Drug Administration. The test is for the early detection of amyloid plaques associated with Alzheimer’s disease in individuals 50 and older exhibiting signs and symptoms of the disease. This gives those affected by Alzheimer’s disease the opportunity to seek treatment, address modifiable risk factors that may slow cognitive decline and consider participating in clinical trials.
What a game changer if we can detect Alzheimer’s disease in the blood BEFORE symptoms.
Alzheimer’s begins 20 years or more before memory loss and other symptoms develop.
· Abnormally high levels of the neurofilament light chain protein in blood, a biomarker of damaged neurons, were found to start an average of 22 years before the median estimated age of symptom onset.
· Research on tau in cerebrospinal fluid suggests that levels of abnormally folded tau in the brain increase as early as two decades before the characteristic mature tau tangles of Alzheimer’s disease appear.
· Researchers also found that glucose metabolism in the brain starts decreasing up to 18 years before expected symptom onset,
· and brain atrophy begins up to 13 years before expected symptom onset.
Underdiagnosis is most pronounced at the earliest stages of dementia when symptoms are mild. Yet stage 3 is where treatment and planning may be most effective (and only 8% of older Americans receive a diagnosis at this stage).
What is noticed in clinical stage 3 of Alzheimer’s disease: thinking, memory and other cognitive problems are noticeable to those affected, friends and family members, but do not interfere with individuals’ ability to carry out everyday activities (mild but detectable functional impairment). They perform their own self cares but may need help with complex iADLs. Biomarker-positive. THIS is when they need to be in with a specialist. It can take a significant amount of time to get in – an appointment with a neurologist should be made!
The potential cost savings of early diagnosis, assuming that 88% of individuals who will develop Alzheimer’s disease would be diagnosed in the mild cognitive impairment phase, rather than the dementia phase or not at all. Approximately $7 trillion could be saved in medical and long-term care costs for individuals who were alive in 2018 and will develop Alzheimer’s disease. Cost savings were the result of (1) a smaller spike in costs immediately before and after diagnosis during the mild cognitive impairment phase compared with the higher-cost dementia phase, and (2) lower medical and long-term care costs for individuals who have diagnosed and managed MCI and dementia compared with individuals with unmanaged MCI and dementia.
2026 alzheimers-facts-and-figures.pdf
