Blood Tests for Alzheimer’s: Reviewing the Best Options

Some of the most talked-about innovations in this space include the Fujirebio blood test and the C2N blood test. Each of which represent a significant leap forward in early detection and disease monitoring. But how do these tests work, and in what ways do they differ? Let’s break it down.

Understanding the Basics of Blood Test for Alzheimer’s

Alzheimer’s is a complex neurological condition that begins long before symptoms appear. Historically, confirming a diagnosis required brain imaging or a lumbar puncture, methods that are either costly, invasive, or hard to access. Blood tests, on the other hand, offer a simpler and more scalable path to detection.

They work by identifying biomarkers (proteins or peptides in the blood) that reflect changes in the brain associated with Alzheimer’s. The earlier these changes are detected, the sooner patients and doctors can make informed care decisions.

Fujirebio and C2N: Two Leaders in Early Detection

Let’s start by looking at who’s behind these two testing platforms.

Fujirebio Diagnostics has been a pioneer in Alzheimer’s research for 25+ years. Their diagnostic technologies originally focused on cerebrospinal fluid (CSF) testing, but the company has since developed plasma-based (blood) tests targeting key Alzheimer’s biomarkers.

Their tests use automated immunoassay systems to detect abnormal levels of amyloid beta and tau proteins: markers that begin shifting years before cognitive symptoms appear.

C2N Diagnostics, based in St. Louis, specializes in advanced mass spectrometry techniques. Their flagship products, the PrecivityAD® and PrecivityAD2™ tests, are designed for patients aged 55 and older with signs of mild cognitive impairment.

These tests estimate the likelihood of amyloid plaque buildup in the brain using a proprietary algorithm known as the Amyloid Probability Score (APS).

How Each Test Works

While both tests are designed to aid early detection of Alzheimer’s, they differ in technology and approach.

Fujirebio Blood Test

The Fujirebio blood test targets three core Alzheimer’s biomarkers in the blood:

Amyloid Beta 1-42 (Aβ42) and 1-40 (Aβ40): A reduced Aβ42/Aβ40 ratio can indicate amyloid buildup.
Phosphorylated Tau (p-Tau): Elevated levels suggest neurofibrillary tangle formation, a key feature of Alzheimer’s pathology.

Fujirebio uses its Lumipulse® platform to quantify these proteins with high sensitivity. This test is particularly scalable in clinical settings due to its automation.

C2N Blood Test

C2N’s PrecivityAD® and PrecivityAD2™ tests also measure Aβ42 and Aβ40, but they go further by combining those results with:

Phospho-Tau217 levels, which offer additional predictive accuracy.
Apolipoprotein E (ApoE) genotype, a known genetic risk factor for Alzheimer’s.

These values are analyzed using high-precision liquid chromatography-tandem mass spectrometry (LC-MS/MS), which provides a highly accurate assessment. The output is an Amyloid Probability Score, which classifies the likelihood of amyloid plaque presence in the brain.

Key Differences: Accuracy, Use Case, and Accessibility

Feature	Fujirebio	C2N
Technology	Automated immunoassay	Mass spectrometry
Biomarkers	Aβ42, Aβ40, p-Tau	Aβ42, Aβ40, p-Tau217, ApoE
Output	Quantified biomarker levels	Amyloid Probability Score (APS)
Use Case	Broad screening and research use	Clinical decision-making in symptomatic patients
FDA Status	Some assays CE marked; research-use-only in U.S.	Available under CLIA certification (not FDA-approved)
Accessibility	Widespread in lab settings	Provider-ordered only; available in most U.S. states
Cost and Insurance	Varies, often in research settings	Typically self-pay; some insurance coverage emerging

While Fujirebio’s platform is built for integration into high-throughput clinical labs, C2N’s test is often used in memory clinics or by specialists for targeted diagnostic support.

When Are These Blood Tests Used?

The primary use case for a blood test for Alzheimer’s is in evaluating patients who show early signs of cognitive decline: typically those experiencing mild memory issues, confusion, or disorientation. These tests can help:

Determine whether symptoms are likely due to Alzheimer’s pathology
Support or rule out the need for more invasive tests like spinal taps or PET scans
Aid in treatment planning, including new disease-modifying therapies

Fujirebio tests may be more commonly used in research or as part of a broader diagnostic panel. C2N tests are often used when a physician needs to confirm whether Alzheimer’s pathology is present before prescribing certain treatments or referring to specialists.

What Should Patients and Physicians Consider?

When deciding whether to pursue a blood test for Alzheimer’s, and which one to use, there are a few key considerations:

Stage of Symptoms: Patients with mild cognitive symptoms may benefit most.
Test Availability: Not all tests are available in every state or lab.
Insurance Coverage: Some C2N tests may require out-of-pocket payment.
Accuracy Needs: If decision-making hinges on a highly specific diagnosis, a test with greater biomarker breadth (like C2N’s) may be preferred.
Physician Experience: Many primary care physicians now refer patients for blood testing before ordering imaging or spinal taps.

Ultimately, the choice of test often depends on what’s available, what the patient is experiencing, and what kind of information the physician needs to move forward.

Have you had a loved one recently diagnosed with Alzheimer’s? If you’re not sure how to move forward, our “Family’s Guide to Alzheimer’s” is a good starting point

Learn More

The Future of Blood Testing for Alzheimer’s

As research continues, these blood-based diagnostics are poised to become a cornerstone of Alzheimer’s detection. Both Fujirebio and C2N are working on expanding their test panels to include new markers, improve accessibility, and tailor diagnostics to diverse populations.

We can also expect future advances in:

Insurance coverage and reimbursement options
Use of blood tests in large-scale screening and clinical trials
Integration with digital tools for monitoring symptoms over time

As tests become more accurate and easier to access, the pathway to early detection will only get smoother.

Knowledge Is Power

Blood tests for Alzheimer’s represent a major shift in how we approach cognitive health. These invaluable tools are bringing earlier answers to more people.

At Daugherty Enterprises, we believe knowledge is power, especially when it comes to navigating an Alzheimer’s diagnosis. If you or a loved one are exploring early detection Alzheimer’s tests, talk to your doctor about the options available and what might be right for your situation. The sooner you know, the more time you have to plan, connect, and get the support you need.