The past diagnosis of Alzheimer’s disease was mainly based on cognitive symptoms, brain imaging scans, and cerebrospinal fluid assays, which were expensive, invasive, or not easily accessible. However, recent technological advancements have led to the development of blood-based biomarkers that could allow for early and inexpensive diagnosis and follow-up of Alzheimer’s disease. These biomarkers have the potential to transform routine clinical care and research but face challenges that need to be addressed before being deployed in clinical settings.
Alzheimer’s disease is a public health crisis affecting an estimated 7 million individuals in the United States. It is a progressively worsening condition that affects cognitive and functional abilities over time. Early diagnosis of Alzheimer’s can aid in better management and delay disease progression. Recent FDA approvals of disease-modifying treatments for Alzheimer’s underscore the importance of early diagnosis, as these drugs are more effective in individuals in the early stages of the disease.
The use of blood-based biomarkers is being explored as an accessible and cost-effective alternative to brain imaging and cerebrospinal fluid biomarkers for Alzheimer’s diagnosis and monitoring. These biomarkers could reduce costs, facilitate the recruitment of participants in clinical trials, monitor treatment outcomes, and help in assessing the risk of Alzheimer’s disease in individuals showing cognitive deficits. Additionally, blood-based biomarkers could assist in the identification of individuals with preclinical Alzheimer’s, enabling early intervention to manage the condition.
Alzheimer’s disease is characterized by abnormal accumulation and aggregation of beta-amyloid and tau proteins in the brain. The ATN framework, developed by the National Institute on Aging and the Alzheimer’s Association, recommends focusing on pathological changes in the brain rather than clinical symptoms for Alzheimer’s diagnosis. Brain imaging scans and cerebrospinal fluid markers are commonly used to assess these changes but are expensive and invasive. The development of ultrasensitive blood-based biomarker assays offers a more accessible and cost-effective alternative for Alzheimer’s diagnosis.
Plasma beta-amyloid-42/beta-amyloid-40 ratio and phosphorylated tau (p-tau) species are potential blood-based biomarkers for Alzheimer’s disease. These biomarkers show promise in accurately reflecting amyloid and tau pathology and neurodegeneration in the brain. Studies have also shown high diagnostic accuracy of blood-based biomarkers in identifying Alzheimer’s disease in primary care clinics and specialized memory care settings. However, challenges such as standardization, validation, and real-world performance need to be addressed before widespread adoption of these tests in clinical practice.
Despite the potential benefits of blood-based biomarkers for Alzheimer’s disease diagnosis and monitoring, challenges such as standardization, validation, and real-world performance need to be addressed. Ongoing studies are evaluating the performance of these biomarkers in diverse populations and developing guidelines for their use and interpretation. The development of infrastructure for delivering these tests in the medical community and addressing insurance coverage issues are also essential for the adoption of blood-based biomarkers in routine clinical care.
