Is Social Media Overselling Alzheimer’s Blood Testing?

Social media posts about Alzheimer’s disease (AD) blood tests frequently promote the tests as a way to detect the disease before symptoms develop, while providing little information about potential harms or the limitations of testing in asymptomatic people, a new study showed.Researchers analyzed posts about blood tests for AD and dementia shared on Facebook, Instagram, and TikTok that collectively reached more than 114 million followers over a period of 11 years.More than one third of the posts promoted blood tests for screening people without cognitive symptoms — which current guidelines do not recommend — and only 12% of those mentioned potential harms such as false-positive results or overdiagnosis.There are currently four AD blood tests cleared by the FDA, including two approved in August. All must be prescribed by a clinician and are indicated only for symptomatic individuals. But at least four companies now offer direct-to-consumer AD tests that aren’t cleared by the FDA.As access to regulated and unregulated AD testing increases, researchers said the new findings raise important concerns for clinicians about how social media may be influencing their patients’ perceptions of these tests.“Social media presents exciting claims about what these new Alzheimer’s blood tests can do. However, consumers should be wary that this excitement may outpace the evidence,” investigator Jenna Smith, PhD, Helen & Robert Ellis Postdoctoral Research Fellow at The University of Sydney School of Public Health in Sydney, Australia, told Medscape Medical News. “Currently, evidence-based recommendations state that healthy people with no symptoms of cognitive decline do not need this blood test.”The research letter was published online on September 15 in the Journal of the American Geriatrics Society.Blood Tests Go OnlineBlood-based biomarkers have expanded options for evaluating AD. Tests measuring biomarkers such as phosphorylated tau (p-tau) can detect AD-related pathology from blood, offering a less invasive alternative to amyloid PET and cerebrospinal fluid testing.However, detecting AD pathology does not necessarily mean that an asymptomatic person will develop cognitive decline or dementia.Jenna Smith, PhDThe 2025 Alzheimer’s Association clinical practice guideline recommends blood-based biomarker testing only for patients with objective cognitive impairment who are being evaluated for suspected AD in specialized memory care settings.In an Alzheimer’s Association survey, 90% of Americans said they would take a blood biomarker test even without symptoms, Medscape Medical News previously reported.As these tests become more accessible, patients are also encountering more information about them online. To study this further, the investigators searched Facebook, Instagram, and TikTok using “dementia blood test” and “Alzheimer’s blood test.” A consumer partner conducted the searches from a newly created account in April 2025.Of 342 posts screened, 218 were initially eligible. Thirty were subsequently excluded because of broken links, inaccessible content, irrelevance, duplication, or non-English content. The final analysis included 188 posts that reached more than 114 million followers between March 2014 and May 2025.Accounts making the posts were classified as individual, company, media organization, government organization, nongovernment organization, community organization, or other. Of the 67 posts made by individuals, 31 were physicians.Screening Claims Omit HarmsOverall, 36% of posts — most of which appeared on TikTok — promoted the usefulness of AD blood tests for people without cognitive symptoms. Only 12% of those mentioned potential harms, including false-positive results or overdiagnosis.Another 59% described blood tests as useful for earlier or improved diagnosis. Of these, 14% specifically described utility in people with objective cognitive decline and 17% referred to subjective cognitive decline. Less than one fifth of posts mentioned the role of a clinician in testing or counseling.Just 5% stated that the tests had no utility or had unclear utility.Most content analyzed in the study was categorized as providing information or education (81%), but two thirds had a promotional tone. Emotional appeals involving fear or hope appeared in just over one third of posts, while 13% explicitly encouraged viewers to get tested.Direct-to-consumer availability was mentioned in 11% of posts, and 22% acknowledged a need for further research.About one third mentioned evidence, but only 24% of those identified a specific study.Explicit financial interests were disclosed in 19% of posts. Accounts with a commercial stake in AD testing had roughly 3.4 times higher odds of claiming that blood tests were useful for asymptomatic screening.Counseling Patients About TestingThe emotional nature of the content posted on social media is particularly worrying, Smith said.“My main concern is that the way they are being presented really plays on people’s emotions, creating excitement and hope around a screening test when the evidence just isn’t there,” she said. “People fear developing dementia — rightly so — but this misleading information risks convincing healthy people to seek out a test that could cause more harm than benefit.”Patients may also misinterpret what a positive result means.“The main misunderstanding is that not all who test positive will go on to develop dementia that impacts their life,” Smith said.For clinicians, conversations about testing should begin by understanding why a patient is interested in learning more about their risk, Smith advised.“Wherever possible, I think clinicians should aim to understand with empathy what is worrying the patient, why this information has appealed to them and what concerns the patients have,” she said.Not a Definitive DiagnosisA major misconception among the general public is that these tests offer a definitive diagnosis, Michael Malek-Ahmadi, PhD, senior bioinformatics scientist at Banner Alzheimer’s Institute in Phoenix, told Medscape Medical News.Michael Malek-Ahmadi, PhD“The tests that have been cleared for clinical use are very good at detecting the underlying biology of Alzheimer’s disease, but we know that many people with Alzheimer’s disease biology do not experience cognitive decline,” said Malek-Ahmadi, who led a 2025 JAMA Neurology study on the diagnostic and prognostic utility of plasma p-tau217 in asymptomatic individuals.Because there is no approved treatment for people without symptoms, screening asymptomatic individuals is not currently reasonable, he said. Social media claims suggesting blood tests can reliably predict who will go on to develop dementia may overstate what is currently known, Malek-Ahmadi added, noting that the ability to accurately predict future disease remains “one of the biggest unanswered questions.”Maria C. Carrillo, PhD, chief science officer and medical affairs lead, Alzheimer’s Association, Chicago, shared that even when an AD blood test is appropriate, the result needs to be interpreted within a broader clinical evaluation.“FDA-cleared Alzheimer’s blood tests can be a helpful tool, but they cannot provide a diagnosis on their own,” Carrillo told Medscape Medical News. “Depending on the specific test and result, additional testing may be needed. Results should always be reviewed by a health care professional as part of a complete evaluation — not interpreted on their own or by nonprofessionals.”These tests are not cleared for people without memory or thinking problems, Carrillo added, because detecting AD-related biology is not the same as diagnosing the disease itself.“There is no approved or recommended clinical action (ie, treatment) for people with no symptoms. A positive result may not mean the same thing in someone without memory or thinking problems,” she said.Disclosure information for study authors is available in the original study publication. Malek-Ahmadi and Carrillo reported no relevant financial interests.