A positive Alzheimer’s blood test in someone without memory problems can create a new category of individuals: those flagged by lab results but not yet symptomatic. Neurologist Dr. Gayatri Devi of Park Avenue Neurology in New York and the Zucker School of Medicine examines these potential cases in a Viewpoint published in JAMA on October 19.
Devi begins with a familiar scenario: a woman in her 50s, healthy with no family history of Alzheimer’s, undergoes a blood test due to fears of future cognitive decline.
For many, the question is no longer just whether to get tested but what happens after a positive result. Identifying risk years before symptoms emerge can impact self-perception, financial planning, and future prospects.
Biomarkers Reshape Self-Identity
The central ethical debate centers on testing asymptomatic individuals, not just test accuracy. A positive result may lead to insurance and employment challenges, along with psychological stress. The term ‘patients-in-waiting,’ borrowed from newborn screening studies, applies here. Many individuals with abnormal biomarkers never develop dementia, creating uncertainty about their condition and future.
Scientific Definitions Drive Policy
Disagreement among experts complicates definitions. The Alzheimer’s Association proposed in 2024 defining Alzheimer’s biologically, including those with abnormal biomarkers. Conversely, the International Working Group recommends testing only when symptoms exist. Devi describes these individuals as ‘flagged by a biomarker, but not conventionally ill.’
Current FDA-cleared tests (e.g., Lumipulse pTau217) are designed for symptomatic adults, not asymptomatic screening. Studies of symptomatic patients show high accuracy, but data for healthy individuals remains limited. A 2025 guideline similarly focuses on those with cognitive impairment.
Insurance Gaps and Hidden Consequences
Federal protections like the Genetic Information Nondiscrimination Act cover genetic tests but exclude biomarker results. This leaves life insurance, disability, and long-term care policies vulnerable. For individuals in their 40s and 50s, positive results could affect coverage or premiums. Decisions about retirement, family planning, and interpreting everyday forgetfulness may also shift.
The Viewpoint is an opinion piece, not a clinical study, and does not alter current guidelines recommending testing for symptomatic individuals only.
Guidance Before Testing
Those considering asymptomatic testing should first consult a clinician to determine if results would inform action. No approved treatments exist for pre-symptomatic individuals, so general health practices (e.g., heart health, exercise) remain advised. Verify FDA clearance, insurance coverage, and result interpretation support. Those with memory issues affecting daily life—such as losing direction or managing finances—should seek clinical evaluation per National Institute on Aging guidelines.
Key Questions Answered
What defines a ‘patient-in-waiting’? An asymptomatic person with abnormal Alzheimer’s biomarkers detected through testing.
Does a positive blood test diagnose Alzheimer’s? Not necessarily. Definitions vary, and many never develop symptoms.
Are asymptomatic tests FDA-approved? No. Cleared tests target symptomatic individuals with cognitive decline.
Can results affect insurance? Yes. Genetic protections exclude biomarker data from life insurance and long-term care coverage.
Is treatment available for pre-symptomatic individuals? No.
When should memory concerns prompt a doctor’s visit? When they disrupt daily life, like failing to manage finances or becoming lost.
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