Clinical utility of plasma Aβ42/40 ratio by LC-MS/MS in Alzheimer's disease assessment.
Level 3 - non-randomized controlled study
Cross-sectional diagnostic accuracy study evaluating a plasma biomarker against amyloid-PET reference imaging.
PubMed 38595851 · doi:10.3389/fneur.2024.1364658
What was done
Plasma Aβ42/40 ratio was measured by LC-MS/MS across 250 specimens with corresponding amyloid PET imaging, clinical diagnosis, and demographic data, as well as 6,192 consecutive clinical specimens submitted for testing.
What was found
The assay demonstrated high sensitivity and negative predictive value (NPV) for Aβ-PET positivity. Assuming moderate PET positivity prevalence, a cutpoint achieved a 99% NPV, estimated to reduce necessary PET scans by approximately 40%. The abstract did not provide exact numerical values for sensitivity, specificity, or biomarker cutoff concentrations.
Why it matters
A high-throughput plasma LC-MS/MS assay for Aβ42/40 can serve as a rule-out test to exclude Alzheimer's disease pathology and significantly reduce reliance on expensive PET imaging.
Limits
The abstract lacks explicit numbers for diagnostic sensitivity, specificity, and exact concentration cutpoints. The reference PET validation cohort was limited to 250 specimens, and the PET reduction rate depends on assumed disease prevalence.
Cited by
- supports Quest Laboratories offers diagnostic testing for Alzheimer's blood biomarkers including p-tau 181, p-tau 217, neurofilament light, and beta-amyloid 42/40 ratio.