Recent breakthroughs in biotechnology have transformed how we detect neurological disease. Now, the U.S. Food and Drug Administration (FDA) has cleared the first blood tests to aid in diagnosing Alzheimer’s disease. These tests offer simpler, faster answers for people experiencing cognitive changes. Find out what you need to know about testing.
FDA cleared Alzheimer’s blood tests
For decades, doctors relied on invasive spinal taps or expensive PET scans to find signs of Alzheimer’s disease. In practice, such testing has only been available to people showing signs of significant cognitive changes. This has greatly reduced the number of people diagnosed early, limiting the effectiveness of available treatments that work best on early-stage disease. Now, blood tests promise to change the way physicians identify individuals at risk of developing Alzheimer’s disease.
In 2025, two blood-based diagnostic tools received FDA clearance. It’s important to keep in mind that these are not “screening” tests for healthy individuals. Instead, the FDA cleared them as diagnostic aids for patients already showing signs of memory loss or cognitive decline.
Fujirebio: Lumipulse G pTau217/β-Amyloid Ratio
The FDA cleared this test in May 2025. It represents the first blood-based biomarker test to receive marketing clearance for Alzheimer’s disease.
- The technology: The test measures the ratio between two proteins: phosphorylated tau (pTau217) and beta-amyloid 1-42. A lower blood ratio strongly correlates with the presence of amyloid plaques in the brain.
- Clinical data: Researchers evaluated the test in a multi-center study involving 499 cognitively impaired adults. Additional research reported positive results, especially in improving the diagnosis by primary care physicians.
- Accuracy: Combining the two blood measures of tau and beta-amyloid as a ratio has proven more reliable than other blood tests and equal to cerebrospinal fluid from a spinal tap. Comparing the blood test to spinal tap data shows positive agreement (sensitivity) of 91.7%. Equally important is specificity, with the study confirming that 97.3% of those with negative plasma results were amyloid negative.
Roche: Elecsys pTau181 Plasma Test
This test, cleared by the FDA in December 2025, specifically helps primary care doctors “rule out” Alzheimer’s-related pathology in patients.
- The Science: It measures pTau181, a protein that increases early in the progression of Alzheimer’s disease.
- Clinical Data: A multicenter study of 312 participants aged 55 and older with cognitive complaints supported the clearance.
- Accuracy: The test boasts a specificity of 97.9%. This means a negative result gives doctors nearly 98% certainty that the patient’s symptoms are not caused by Alzheimer’s pathology.
- Limitation: The sensitivity or positive predictive value of this test is low (approximately 22.4% in primary care). The test is only meant to rule out tau pathology.
Research comparing the Lumipulse to Elecsys systems reported that both Lumipulse and Elecsys pTau217 (not yet FDA-approved) were comparable in sensitivity accuracy, while the Elecsys pTau181 performed lower. However, these blood biomarker tests meet recommended guidelines for their purpose, including sensitivity ≥ 90% and specificity ≥ 85% in primary care.
Can consumers get these tests directly?
Headlines often suggest these tests are available to the general public, but the reality is more restricted:
- Physician Requirement: FDA-cleared tests from Roche and Fujirebio require a doctor’s order. You cannot currently buy these as “over-the-counter” kits.
- Professional Lab Processing: Manufacturers sell these diagnostic kits to large clinical laboratories (like Quest Diagnostics). Because these are “In-Vitro Diagnostic” (IVD) tools for professional use, you won’t find a “buy now” button on the manufacturer’s website.
- Direct-to-Consumer (DTC) Options: Some companies, such as Quest, offer “consumer-initiated” testing. While you can start the process online, an independent physician must still review and authorize the test to ensure it’s appropriate for your symptoms.
“A blood test of this kind is going to greatly expand clinicians’ ability to confirm that Alzheimer’s is present. “
— Dr. Nathaniel Chin, Associate Professor at the University of Wisconsin School of Medicine and Public Health, and Medical Director for the Wisconsin Registry for Alzheimer’s Prevention study that provided samples to evaluate the Lumipulse product.
Warnings and essential considerations
Testing for Alzheimer’s markers involves more than just a needle prick. Working with an appropriate healthcare provider will ensure accurate interpretation of results and guidance on next steps.
Consider these factors before moving forward:
- Prediction vs. presence: These tests do not predict whether a healthy person will develop Alzheimer’s years from now. They only detect whether the disease’s biological markers are present in someone who is already experiencing symptoms.
- Risk of false positives: In healthy populations without symptoms, the risk of false-positive results increases. This can cause significant “diagnostic anxiety” without providing clinical benefit.
- The importance of clinical context: Memory loss can stem from many treatable issues, including vitamin B12 deficiency, thyroid dysfunction, or depression. You must coordinate with a healthcare provider to rule out these reversible conditions.
- Treatment access: Current FDA-approved treatments, such as Leqembi and Kisunla, require confirmation of amyloid pathology. A blood test is often the first step toward qualifying for these therapies.
- Population differences: Blood biomarkers can vary depending on race and ethnicity. Additional validation in diverse populations and the development of specific reference ranges are required.
What’s next for Alzheimer’s blood tests?
As the research on blood tests for Alzheimer’s disease moves forward, we can expect improvements in diagnostic accuracy and additional validation in different racial-ethnic groups. Additionally, physicians need to be prepared for their use and interpretation. The Alzheimer’s Association published a Clinical Practice Guideline on the use of blood-based biomarkers to aid physicians in making the best use of blood tests to aid their patients.
There are many ways to reduce your risk of Alzheimer’s and dementia. Check out our articles on these topics for modifiable risk factors you can start addressing today.
