Researchers are cautioning that social media could be encouraging healthy individuals to undergo Alzheimer's blood tests, leading to significant anxiety about biological markers that might never result in dementia. These blood-based biomarker tests, such as p-tau217 and p-tau181, identify biological indicators of brain changes linked to Alzheimer's disease.
Despite their ability to detect early signs, there is a global consensus among leading neurological organisations, including the Alzheimer's Association, that these tests should not be used for healthy people without symptoms. Clinicians and peak bodies also state that the tests should not be used in isolation for diagnosis but must be combined with other medical assessments.
Dr Jenna Smith from the University of Sydney's school of public health and her colleagues analysed 188 social media posts mentioning Alzheimer's or dementia and blood tests. They found that more than one-third of these posts promoted the tests for people without symptoms. Accounts with explicit financial interests were over three times more likely to do so.
Dr Smith highlighted potential harms, including unnecessary diagnoses and a lack of clear pathways for next steps. A positive result for biological markers does not guarantee the development of clinical dementia symptoms. Research on treatments has focused on individuals with mild cognitive impairment or dementia, so their effectiveness for healthy people who test positive is unknown.
Professor Susan Kurrle, president of the Australian and New Zealand Society for Geriatric Medicine, emphasised that doctors should only order these tests under specific circumstances, where there is a high pre-test probability of early Alzheimer's disease. She warned that false positives could lead to undue belief in inevitable dementia, while false negatives might deter individuals from addressing modifiable risk factors.