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July 29, 2025
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Alzheimer’s Association provides initial clinical guidance on blood-based biomarkers

Key takeaways:

  • Blood-based biomarker testing should not be the sole method of Alzheimer’s disease diagnosis.
  • These biomarker tests should be used only after a comprehensive clinical evaluation by a qualified specialist.

Blood-based biomarker testing can be used to diagnose Alzheimer’s disease but must have a significantly high degree of sensitivity and specificity for clinicians to employ them as the sole diagnostic method.

“Blood tests are currently being used in a wide range of clinical settings due to their relatively low cost and higher accessibility vs. other testing modalities,” Sheena Aurora, MD, vice president of medical affairs at the Alzheimer’s Association, told Healio, about the organization’s new clinical guidelines introduced at the Alzheimer’s Association International Conference.

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“While the current guidelines provide data for tests conducted in the specialty setting, our guideline recommendations can inform health care providers in all settings regarding the current state of evidence,” she said.

The full recommendation, which was also published in Alzheimer’s & Dementia, sought to provide specialists an “evidence-based, brand-agnostic” path toward more rapid and accurate AD diagnoses through this relatively new method.

The two recommendations that form the basis of the new guideline are as follows:

  • Blood-based biomarker (BBM) testing with at least 90% sensitivity and at least 75% specificity can be used as diagnostic triage, where a negative result rules out AD pathology and a positive result should be confirmed by additional biomarker testing such as cerebrospinal fluid (CSF) or amyloid positron emission tomography (PET).
  • BBM tests with sensitivity and specificity of at least 90% may be used as an alternative for CSF or PET testing.

The Alzheimer’s Association (AA) gathered a panel of 11 clinicians from a broad range of health care spaces and conducted a systematic review of 49 observational studies and 31 BBM tests to create evidence-based recommendations for BBM use for those with objective cognitive impairment, including individuals diagnosed with mild cognitive impairment or dementia.

The guidelines were further informed through suggestions from the AA’s early-stage advisory group, which considered both public comment and experiences of patients in the early stage of the condition.

Under consideration by the panel were most of the current BBMs available, which measure abnormal forms of protein that are likely indicators of disease presence from both plasma phosphorylated tau (p-tau) and amyloid-beta testing, including p-tau181, 217 and 231, along with a ratio of p-tau217 to non p-tau217 and the ratio of amyloid-beta 42 to 40.

Further shaping the guidelines were decisions made by the panel to decline endorsing specific biomarker tests to ensure proper blinding and reduce the possibility of bias. The panel chose instead to emphasize the accuracy of the reviewed data, and the accuracy of the testing itself should act as resources from which clinicians should make their decisions.

“This is the first guideline to utilize the [Grading of Recommendations Assessment, Development and Evaluation] methodology on blood-based biomarker testing for Alzheimer’s disease,” Aurora said. “The field is rapidly evolving, and the panel’s position is that ranking or endorsing specific tests is premature at this time.”

As such, the panel added two more recommendations and a “good practice statement” to steer BBM utilization in Alzheimer’s-related diagnostic workups:

  • High-sensitivity BBMs are recommended for diagnostic triage for patients with objective cognitive impairment seeking specialized treatment for memory issues.
  • Testing that incorporates both high sensitivity and high specificity is recommended to confirm AD during diagnostic workups in the same patient population.
  • No BBMs should be sought or used before a comprehensive clinical evaluation by a qualified specialist, with test results interpreted in the proper clinical context.

“The broad adoption of the Alzheimer’s Association’s CPG on blood biomarkers by specialists could lead to quicker and more accurate diagnoses, as well as better outcomes for individuals and families affected by Alzheimer’s,” Aurora said.

The guideline is available online at ALZPro, which is the Alzheimer’s Association’s platform for clinical guidelines, education and training, research, and tools for researchers, clinicians, and dementia care providers.

According to the AA, expected updates to the clinical practice guidelines should include cognitive assessment tools (Fall 2025), clinical implementation of staging criteria and treatment (2026) and steps for prevention of AD and other related dementias (2027).

“This is a pivotal moment in Alzheimer’s care,” Maria C. Carillo, PhD, chief science officer and medical affairs lead at the Alzheimer’s Association, said in a related release. “Adoption of these recommendations will lead to quicker, more accessible, more accurate diagnoses and better outcomes for individuals and families.”

Reference:

Alzheimer’s Association releases its first clinical practice guideline for blood-based biomarker tests. https://aaic.alz.org/releases-2025/clinical-practice-guideline-blood-based-biomarkers.asp. Published July 29, 2025. Accessed July 29, 2025.

For more information:

Sheena Aurora, MD, and Maria C. Carillo, PhD, can be reached at neurology@healio.com.