New Delhi: Alzheimer’s Disease (AD) is the most common cause of dementia, impacting nearly 55 million people globally, including 10 million new cases each year, according to the World Health Organisation. In India alone, more than 5.3 million people live with dementia, and this number is projected to triple by 2050. Traditionally, Alzheimer’s is diagnosed only after noticeable memory loss and cognitive decline have already occurred, by which time there has been extensive and irreversible brain damage. This makes early detection crucial—not just for slowing disease progression and improving quality of life, but also for enabling timely care and treatment effectiveness.
Dr. Vinay Goyal, Chairman, Neurology, Neurosciences, Medanta, Gurugram, explained how the same can have an impact on diagnosis rates.
To address this gap, researchers are turning to blood biomarkers—simple biological signals that can indicate the onset of disease much earlier than current diagnostic methods. These markers have the potential to revolutionize Alzheimer’s diagnosis by shifting the focus from late-stage detection to early intervention.
Blood biomarkers: A new frontier in Alzheimer’s diagnosis
Blood biomarkers are molecules or proteins in the blood that act as biological signals of health or disease. In Alzheimer’s, abnormal proteins such as amyloid-beta and tau begin accumulating in the brain years before symptoms like memory loss appear. Detecting these proteins through a simple blood test could allow doctors to identify at-risk individuals much earlier than current methods.
In recent years, biomarker research has advanced rapidly. In 2025, the first blood test measuring amyloid-beta ratios received U.S. FDA approval, showing accuracy comparable to PET scans. New markers like phosphorylated tau (p-tau) and neurofilament light chain (NFL) are also being explored for both diagnosis and monitoring disease progression, with some tests reaching over 90% accuracy. Researchers are now working to standardize these tests globally, paving the way for routine use in clinical practice. If widely adopted, blood biomarkers could transform dementia care by enabling early intervention rather than late-stage management.
Why early detection matters
Identifying those at risk for dementia earlier has several benefits, including:
- Timely Intervention: Lifestyle changes such as exercise, cognitive training, and Mediterranean diet have been shown to slow disease progression when improvement is possible.
- Clinical Trials: Individuals identified earlier as having risk for dementia can be considered for clinical trials for new drugs that target amyloid or tau pathology, for example.
- Planning: Families and care partners can engage in advanced planning for future care needs.
Overcoming barriers to Alzheimer’s diagnosis
Alzheimer’s disease affects millions worldwide, with nearly 10 million new cases each year, and India alone is projected to reach 7.6 million cases by 2030. Until recently, diagnosis relied on costly and invasive methods like PET scans and spinal fluid analysis, while cognitive testing often detected the disease only after significant brain damage.
Blood biomarkers now offer a simpler, less invasive, and more affordable alternative. A routine blood test can reveal Alzheimer ‘s-related changes years before symptoms appear, enabling earlier diagnosis, timely interventions, participation in clinical trials, and lifestyle adjustments that may slow progression.
The advent of blood biomarkers in Alzheimer’s diagnosis represents a sea change away from complicated, expensive, and invasive testing methods to easy and accessible testing methods. Ultimately, they foreseeably promise to allow detection of the disease to occur much earlier in the course of the disease, thereby facilitating timely treatment for millions of people worldwide, but also improving outcomes by enabling them to plan for and generally improve their quality of life in the face of an extremely trying course.