Lumipulse G is an FDA-cleared biomarker assay used to aid in the diagnosis of Alzheimer’s disease. The newest version is the Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio, which is the first FDA-cleared blood test to help detect amyloid pathology associated with Alzheimer’s disease.

What does it measure?

It measures the ratio of:

• Phosphorylated tau-217 (pTau217)
• β-Amyloid 1-42 (Aβ42)

This ratio predicts the presence of amyloid plaques in the brain, a pathological hallmark of Alzheimer’s disease.

Indications

• Adults ≥55 years
• Patients with signs and symptoms of cognitive impairment being evaluated for Alzheimer’s disease.
• Not intended as a screening test for asymptomatic individuals

Advantages

• Requires only a blood sample.
• Less invasive than lumbar puncture.
• Less expensive and more accessible than amyloid PET imaging.
• Helps determine which patients may benefit from confirmatory testing or anti-amyloid therapies. (U.S. Food and Drug Administration)

Interpretation

• Positive test: Suggests a high likelihood of cerebral amyloid plaques.
• Negative test: Makes significant amyloid pathology less likely.
• Does not establish the diagnosis of Alzheimer’s disease by itself; results must be interpreted in conjunction with clinical assessment, neuropsychological testing, and imaging when appropriate. (FDA Access Data)

Previous Lumipulse assay

An earlier Lumipulse G β-Amyloid Ratio (Aβ42/Aβ40) assay used cerebrospinal fluid (CSF) obtained by lumbar puncture. The newer plasma pTau217/Aβ42 ratio assay is the first FDA-cleared blood-based version. (aafp.org)

 

Exam pearl for NEET PG and INICET exams

Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio

• ✔ First FDA-cleared blood test for Alzheimer’s disease (2025)
• ✔ Detects amyloid pathology, not dementia itself
• ✔ Used in symptomatic patients aged ≥55 years
• ✔ Cannot replace clinical diagnosis or be used as a standalone screening test

 

 

Dr Marwah