TORONTO \u2014 An expert panel convened by the Alzheimer\u2019s Association has released the first clinical guidelines to help clinicians choose the most appropriate blood-based biomarker (BBM) test to aid in the diagnosis of Alzheimer\u2019s disease (AD).<\/p>\n
The evidence-based guideline recommends that tests with \u2265 90% sensitivity and specificity can serve as a substitute for amyloid PET or cerebrospinal fluid (CSF) biomarker testing.<\/p>\n
Tests with \u2265 90% sensitivity but only \u2265 75% specificity should be used as a triaging test. In this case, a negative result rules out AD pathology with high probability and a positive result should be confirmed with CSF or PET testing.<\/p>\n
Evidence-based guidelines are key to standardizing the use of BBMs in clinical practice, Rebecca M. Edelmayer, PhD, vice president of scientific engagement for the Alzheimer\u2019s Association, told Medscape Medical News.<\/p>\n
\u201cThe whole purpose of developing the clinical practice guideline is to try to create pragmatic recommendations for clinicians on how to choose the right test for the right patient at the right time,\u201d Edelmayer said.<\/p>\n
This new guideline is the first step in a developing process, she added. \u201cThe blood-based biomarker area is still a burgeoning field.\u201d<\/p>\n
The findings were presented on July 29 at the Alzheimer\u2019s Association International Conference (AAIC) 2025<\/a> and published online<\/a> simultaneously in Alzheimer\u2019s & Dementia.<\/p>\n Meeting a Need<\/p>\n With the approval of anti-amyloid beta (A\u03b2) therapies to treat early symptomatic disease, more rapid and accurate diagnosis of AD is becoming increasingly important. A number of different BBM tests are available to clinicians, but the lack of clinical practice guidelines has hindered more widespread use of the diagnostic tools, guidelines authors wrote.<\/p>\n A panel of clinical experts, researchers with experience and technical knowledge surrounding BBM, and guideline methodologists conducted a systematic review of the literature to assess the accuracy of BBMs in detecting amyloid pathology for triaging (\u2265 90% sensitivity, \u2265 75% specificity) and confirmatory (\u2265 90% sensitivity and specificity) diagnostic workup.<\/p>\n After a review of 1050 papers, 49 observational studies of 31 different BBM tests were selected for inclusion.<\/p>\n The BBMs of interest included plasma phosphorylated-tau (p-tau) and A\u03b2 tests measuring these analytes: p-tau217, the ratio of p-tau217 to non-p-tau217 \u00d7100 (%p-tau17), p-tau181, p-tau231, and the ratio of A\u03b242 to A\u03b240. The reference standard tests included CSF, amyloid PET, or neuropathology examination.<\/p>\n The relatively low-cost BBM tests are minimally invasive compared with PET and CSF tests and can significantly reduce the physical discomfort and anxiety often associated with lumbar puncture or PET imaging procedures, the authors wrote.<\/p>\n The systematic review focused on single analytes, not combinations of different analytes, sometimes referred to a \u201cblood panel,\u201d noted Edelmayer.<\/p>\n Using predefined decision thresholds, the panel determined whether tests have sufficient diagnostic accuracy to be used as a triaging test where a positive test is to be confirmed by PET or CSF, sufficient diagnostic accuracy as a confirmatory test to replace PET or CSF, or insufficient diagnostic accuracy to recommend current use in clinical practice.<\/p>\n The recommendations are focused on individuals with either mild cognitive impairment or dementia who are undergoing diagnostic assessment by providers trained and experienced in memory disorders, where AD is the suspected underlying etiology.<\/p>\n The guideline does not endorse specific tests or rank them.<\/p>\n \u201cWe just don\u2019t have enough data at this time,\u201d said Edelmayer. \u201cWe\u2019re not ready to pick one single test out of a lineup of tests to say this test is performing much better in a comparative analysis and through systematic review evidence than another test.\u201d<\/p>\n Accurate Predictors<\/p>\n Researchers now have a clearer picture of how AD pathology evolved over time, with changes in some tau biomarkers occurring very early on, said Edelmayer.<\/p>\n \u201cWhat we\u2019ve learned from all of the evidence so far is that some of these biomarkers, like tau 217, tend to be very accurate predictors of Alzheimer\u2019s disease biology in the brain, and they can be used to aid in the diagnostic process early on, sometimes even before tau tangle formations can be visualized with brain imaging.\u201d<\/p>\n The guideline authors noted some limitations of the evidence. For example, undesirable effects of BBM testing could include false positive or false negative results, which could delay accurate diagnosis and treatment.<\/p>\n The authors also cautioned that there\u2019s significant variability in the accuracy of diagnostic tests and many commercially available BBM tests do not meet accuracy thresholds.<\/p>\n Edelmayer stressed this is the first iteration of the clinical practice guideline and the expert panel is already working on next steps, including determining if these biomarkers can be used as confirmatory or triage tests in cognitively unimpaired people and in a primary care setting.<\/p>\n The tests aren\u2019t a substitute for comprehensive clinical evaluation by a healthcare professional, said David Knopman, MD, a clinical neurologist and researcher at the Mayo Clinic in Rochester, Minnesota, who commented on the new guidelines for Medscape Medical News.<\/p>\n \u201cThe use of any AD-specific biomarker is dependent on the context,\u201d he said. \u201cFor example, the history or no history of cognitive impairment, the objective cognitive assessment, and the presence or absence of features of non-AD biologics.\u201d<\/p>\n While he noted the guideline was reasonable for the separate functions of triaging and confirming AD biology, as with any such document, no matter how thoughtfully constructed, there\u2019s the risk that people ignore stipulations in the recommendation.<\/p>\n \u201cSo people without cognitive impairment will be captured. There\u2019s also the risk that the memory disorder clinic is not well versed in non-Alzheimer causes of memory impairment,\u201d he said.<\/p>\n Edelmayer is an employee of the Alzheimer\u2019s Association. Knopman reported no relevant conflicts of interest.<\/p>\n","protected":false},"excerpt":{"rendered":"TORONTO \u2014 An expert panel convened by the Alzheimer\u2019s Association has released the first clinical guidelines to help…\n","protected":false},"author":2,"featured_media":36993,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[27313,27315,27314,2768,49,48,27320,4756,27319,4757,84,27317,27322,27316,27318,27321],"class_list":["post-36992","post","type-post","status-publish","format-standard","has-post-thumbnail","category-health","tag-alzheimer-disease-alzheimers-disease-alzheimers","tag-biological-marker","tag-biomarker","tag-blood","tag-ca","tag-canada","tag-cerebrospinal-fluid","tag-clinical-guidelines","tag-csf","tag-guidelines","tag-health","tag-mbda","tag-mild-cognitive-impairment-minimal-cognitive-impairment-mci-mild-cognitive-impairment-mci","tag-multi-biomarker-disease-activity","tag-multibiomarker-disease-activity","tag-positron-emission-tomography-pet-pet-scan-positron-emission-tomography-pet"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/36992","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=36992"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/36992\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/36993"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=36992"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=36992"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=36992"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}