New blood tests that may identify signs of Alzheimer’s disease years before symptoms appear have generated significant interest among those concerned about dementia risk. However, experts caution that these tests are not yet ready for widespread use, particularly among individuals without cognitive symptoms.
The U.S. Food and Drug Administration has authorized four blood tests designed to assist clinicians in diagnosing Alzheimer’s disease in patients exhibiting memory issues or other cognitive impairments. Early diagnosis can enable access to medications that may modestly slow the progression of symptoms. Despite this, some laboratories and online services offer tests to people without symptoms, a practice that specialists advise against.
Nicholas Ashton, a testing expert at Banner Health in Arizona, emphasized that these blood tests should currently be limited to research settings and not used as routine screening tools for asymptomatic individuals. “The worried well should not be getting those tests,” Ashton said.
Instead, health professionals recommend focusing on modifiable risk factors that may delay or reduce dementia onset. A major study led by Dr. Josef Coresh of NYU Langone Health found that individuals who entered middle age without conditions like high blood pressure, diabetes, or smoking lived an average of nearly 13 years longer without dementia compared to those with all three risk factors. Coresh underscored the importance of early and aggressive management of these health issues.
Alzheimer’s is characterized by the accumulation of abnormal protein markers in the brain, including beta-amyloid plaques and tau tangles. Blood tests measuring a specific form of tau protein, p-tau217, appear to correlate with amyloid buildup in symptomatic individuals. However, their predictive value in symptom-free people remains limited. Research from Mass General Brigham found that older adults with elevated p-tau217 levels had a 38% chance of developing cognitive impairment within five years, increasing over a decade. Still, a positive result indicates increased risk rather than a definitive diagnosis, and false positives can occur.
Mark Yost, 60, from Phoenix, participated in a Banner Health study of these tests. Though cognitively normal, he sought to understand his risk. His results were classified as “intermediate,” suggesting some amyloid presence but not an alarmingly high level. Yost described the uncertainty as disappointing but remains focused on preventive lifestyle measures such as exercise and mentally engaging activities.
Beyond testing, evidence supports lifestyle interventions to maintain brain health. A recent large trial demonstrated that regular physical activity, including aerobic exercise and resistance training, combined with adherence to the MIND diet—rich in leafy greens, berries, whole grains, poultry, and fish—can slow cognitive decline. Additional recommendations include ensuring sufficient sleep, treating hearing loss, avoiding social isolation, and engaging the brain through mental challenges.
The NYU study’s findings reinforce the link between cardiovascular health and brain function. Over 12,000 individuals tracked for decades showed that the absence of high blood pressure, diabetes, and smoking in middle age corresponds with better long-term cognitive outcomes. Even carriers of the APOE4 gene, which increases Alzheimer’s risk, benefited from healthy habits during midlife. Coresh highlighted the proven benefits of early and sustained blood pressure control for brain health.
While the outlook for Alzheimer’s blood testing is evolving, ongoing clinical trials aim to clarify whether existing Alzheimer’s treatments might be effective before symptoms develop. These findings could influence future recommendations regarding the use of these tests. For now, experts advise focusing on well-established preventive measures rather than relying on early diagnostic blood tests.