In the spring of 2025, the U.S. Food and Drug Administration (FDA) cleared the first blood test to aid in the diagnosis of Alzheimer’s disease. MBWC clinicians and researchers offer this Q&A to our community members to answer some common questions about blood tests for Alzheimer's.
Page last updated: August 18, 2025
Who is this new blood test for?
The Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio is for the early detection of amyloid plaques associated with Alzheimer’s disease in adult patients, aged 55 years and older, exhibiting signs and symptoms.
What does a positive Lumipulse blood test mean?
A positive test means that the biological processes underlying Alzheimer’s disease are probably ongoing in a particular patient. These processes actually go on for years before people have symptoms, and the test on its own cannot tell us where someone is on the continuum of preclinical disease to symptomatic disease. For this reason, it is important to take symptoms into account in ordering and interpreting the test.
Is the blood test available from primary care physicians, or does someone need to go to a specialty center?
Further research is needed to determine if the test is useful in the general population before your primary care physician can use the test. Blood-based biomarkers, including the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio, are currently useful in the setting of a specialty referral clinic.
Will it still be necessary to get brain scans for a definitive diagnosis, or can this blood test now be used on its own?
Brain scans, such as MRI, will continue as a necessary diagnostic test for establishing a definitive diagnosis. PET scans also contribute important information in selected cases. But blood tests will probably reduce the need for some PET scans.
When will the MBWC begin offering this test?
The UW Memory and Brain Wellness Center has been offering a similar test processed by the Mayo Clinic that evaluates Ptau217 level since April 2024. The clinic has no plans to make any changes now, but will consider an alternative blood test should it be reliably reimbursed by medical insurance.
Will this test help a doctor to tailor a patient’s treatment? Will it determine eligibility for lecanemab or donanemab?
The MBWC has been using the Ptau217 ordered in the clinic since April 2024 to confirm the Alzheimer’s disease diagnosis under certain conditions. It can be used to determine eligibility for lecanemab or donanemab. For our Q&A on these infusion treatments, please visit: Amyloid-Clearing Infusion Treatments for Early-Stage Alzheimer’s Disease Resource Page
If this blood test does not confirm an Alzheimer’s diagnosis for a person experiencing signs and symptoms of cognitive decline, what are the next steps?
The next steps will be to perform additional tests to determine the actual underlying condition. These tests consist of a lumbar puncture to assess cerebrospinal fluid or a PET scan.
How was this new diagnostic method tested?
There have been extensive studies evaluating the accuracy, sensitivity, and specificity of these blood tests in Alzheimer’s disease, including comparing them to amyloid PET scans in the same patients. We know that in certain circumstances, the sensitivity and specificity, and overall accuracy of a blood biomarker test can be >90%. These results give MBWC clinicians more confidence in the results from this test.
What is the significance of this new blood test in the Alzheimer’s field? What does it mean for the future?
A blood draw is less expensive and more accessible. Many people feel more comfortable with a blood draw than a CSF draw or brain scan. An accurate blood test means that in the future, once more study has been done, your primary care physician can order a blood test to determine if a patient is likely to have Alzheimer’s pathology in the brain. This could speed up the time to treatment.