Table of Contents
Lumipulse blood test measures p-tau217/β-amyloid 1-42 ratio to detect Alzheimer's amyloid pathology. FDA-cleared. Quest offers since 2025. 92-97% accurate vs PET and spinal tap. Simple blood draw replaces invasive procedures. Not standalone diagnosis, part of physician evaluation with clinical examination. For adults with cognitive decline, not asymptomatic screening.
Question | Answer |
|---|---|
What does the Lumipulse blood test measure? | It measures the ratio of p-tau217 to β-amyloid 1-42 proteins in blood to indicate Alzheimer's amyloid pathology. |
How accurate is the Lumipulse test vs PET scans and spinal tap? | The Lumipulse test agrees with gold-standard PET scans and spinal fluid analysis 92 to 97 percent of the time. |
Who should get the Lumipulse test? | Adults with cognitive impairment being evaluated for Alzheimer's disease, not for screening asymptomatic individuals. |
Where can patients access the Lumipulse test? | Quest Diagnostics has offered the Lumipulse test through its national laboratory network since 2025. |
Is the Lumipulse test a standalone Alzheimer's diagnosis? | No, it aids diagnosis but must be interpreted by a physician alongside clinical evaluation and medical history. |
What is the Lumipulse blood test for Alzheimer's disease.
The Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio is an FDA-cleared in-vitro diagnostic (IVD) blood test developed by Fujirebio. It aids in evaluating adults with cognitive impairment for Alzheimer's disease by measuring specific protein biomarkers in the blood.
Biomarkers Measured
The test quantifies the ratio of two key proteins:
Biomarker | Change in Alzheimer's | Role in Test |
|---|---|---|
p-Tau217 | Increases | Indicates tau pathology |
β-Amyloid 1-42 | Decreases | Indicates amyloid plaque buildup |
A specific ratio of these proteins strongly correlates with the presence of amyloid plaques in the brain, a hallmark of Alzheimer's.
How It Works
A standard blood draw is performed. The sample is analyzed using Fujirebio's Lumipulse automated immunoassay system. The technology provides a numerical result that helps determine the likelihood of amyloid pathology.
Intended Use & Limitations
Lumipulse is not a standalone diagnostic. It is intended as an aid in diagnosis for patients with symptoms of cognitive decline. Results must be interpreted by a physician alongside clinical evaluation, medical history, and other diagnostic tools like brain imaging. It does not diagnose other causes of dementia.
Key Advantages
- Less invasive: Simple blood draw vs. lumbar puncture or PET scan.
- More accessible: Can be performed in clinical lab settings like Quest Diagnostics.
- Objective biomarker: Provides quantitative data to support clinical assessment.
Quest Diagnostics began offering the Lumipulse test in 2025, making this advanced biomarker analysis more widely available to help guide patient care decisions.
How does the Lumipulse test measure brain biomarkers from a simple blood draw.
The Lumipulse test uses a standard blood draw to detect tiny protein fragments that leak from the brain into circulation. It measures two specific biomarkers: phosphorylated tau 217 (p-tau217) and beta-amyloid 1-42 (Aβ42). Their ratio provides a window into Alzheimer's pathology.
Where the Biomarkers Come From
In Alzheimer's disease, amyloid plaques and tau tangles form in the brain. These abnormal protein aggregates shed fragments that cross the blood-brain barrier into the bloodstream.
- β-amyloid 1-42 decreases in blood as it gets trapped in brain plaques.
- p-tau217 increases as tau tangles spread.
Both proteins travel in blood at extremely low concentrations. The Lumipulse platform detects them with high sensitivity.
Analytical Process: CLEIA
The test runs on Fujirebio's automated Lumipulse G system using chemiluminescent enzyme immunoassay (CLEIA).
- A blood sample is mixed with antibodies that specifically bind p-tau217 and Aβ42.
- Each antibody is linked to an enzyme that produces light when activated.
- The system measures the amount of light emitted, which corresponds to the concentration of each biomarker.
- Software automatically calculates the p-tau217/Aβ42 ratio.
Why the Ratio Matters More Than Single Values
Biomarker | Typical Change in Alzheimer's | Signal Type |
|---|---|---|
p-tau217 | Rises | Increases light signal |
β-amyloid 1-42 | Falls | Decreases light signal |
Ratio (p-tau217/Aβ42) | Markedly increases | Amplifies discrimination |
The combined ratio normalizes individual variability and strengthens the correlation with brain amyloid status.
From Blood Draw to Result
The test requires no special preparation. Blood is collected in a standard EDTA tube. After processing, the Lumipulse system returns results in about 35 minutes. Quest Diagnostics began offering the test in 2025 through its national laboratory network.
Lumipulse accuracy matches PET scans and spinal fluid tests over 90% of the time.
Multiple clinical studies demonstrate that the Lumipulse blood test agrees with gold-standard PET scans and spinal fluid analysis 92 to 97 percent of the time. This high concordance makes it a reliable, non-invasive alternative for detecting Alzheimer's-related amyloid pathology.
Direct Comparison With Gold Standards
Diagnostic Method | Agreement With Lumipulse | Invasiveness | Cost |
|---|---|---|---|
Amyloid PET scan | 92–97% | Low (radiation exposure) | Very high |
Spinal fluid (CSF) analysis | 92–97% | High (lumbar puncture) | High |
Lumipulse blood test | Reference | Low (blood draw) | Moderate |
Key Study Findings
In the FDA clearance submission, Fujirebio reported results from a prospective clinical study evaluating patients with cognitive impairment.
- Sensitivity exceeded 90% – correctly identified people with amyloid plaques.
- Specificity exceeded 90% – accurately ruled out those without plaques.
- Negative predictive value was high, meaning a negative result strongly reduces the likelihood of Alzheimer's pathology.
Why Accuracy Matters
A test with greater than 90% accuracy reduces unnecessary follow-up procedures like PET scans or lumbar punctures. This speeds up diagnosis and lowers healthcare costs. The high agreement also gives clinicians confidence to base treatment decisions on the blood result.
Published Independent Validation
Mayo Clinic, Fisher Center for Alzheimer's Research, and other institutions have published data confirming Lumipulse accuracy in diverse patient populations. The consistent performance across multiple sites reinforces its clinical utility.
Quest Diagnostics now offers the Lumipulse test for patients with cognitive decline.
Quest Diagnostics began offering the Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio test in 2025. This makes the FDA-cleared Alzheimer's biomarker test accessible through the largest clinical laboratory network in the United States.
How Patients Access the Test
Physicians order the Lumipulse test for patients experiencing cognitive symptoms like memory loss or confusion. The patient has a standard blood draw at any Quest patient service center. The sample is processed in Quest's certified laboratories using the Fujirebio Lumipulse system. Results are returned to the ordering physician within days.
Clinical Pathway Integration
The test fits into the standard diagnostic workup for Alzheimer's. It provides an objective biomarker result before considering expensive or invasive follow-ups.
- Patient presents with cognitive complaints.
- Physician conducts clinical assessment and orders Lumipulse.
- Blood draw at Quest.
- Result indicates likelihood of amyloid pathology (positive/negative).
- Result guides next steps: monitor, treat, or confirm with PET/spinal tap.
Advantages of the Quest Model
Traditional Diagnostic Path | With Lumipulse via Quest |
|---|---|
Clinical assessment → PET scan or lumbar puncture | Clinical assessment → Blood test → Targeted follow-up if needed |
High cost, limited availability | Lower cost, nationwide access |
Invasive or radiation exposure | Minimally invasive |
Long wait times for scans | Faster initial results |
Who Should Consider the Test
The Lumipulse test is indicated for adults with cognitive impairment being evaluated for Alzheimer's disease. It is not for screening asymptomatic individuals. A positive result supports the presence of amyloid pathology. A negative result makes Alzheimer's less likely but does not completely rule it out.
Patients concerned about memory should speak with their doctor about whether a blood-based biomarker test like Lumipulse is appropriate for their diagnostic evaluation.