Independent study demonstrates amyloid probability score accurately indicates amyloid pathology

Area of Science:

• Neurology
• Biomarker Discovery
• Medical Diagnostics

Background:

• The amyloid probability score (APS) is derived from the PrecivityAD® blood test, utilizing plasma Aβ42/40 ratio, ApoE proteotype, and age.
• It assesses the likelihood of brain amyloid plaques in individuals with cognitive impairment undergoing Alzheimer's disease evaluation.

Purpose of the Study:

• To independently validate the efficacy of the pre-established APS algorithm and its cutoff values.
• To confirm the algorithm's ability to differentiate between amyloid-positive and amyloid-negative individuals.

Main Methods:

• Diagnostic performance analysis of the PrecivityAD test in 200 Australian Imaging, Biomarker & Lifestyle Flagship Study of Aging (AIBL) participants.
• Inclusion of cognitively impaired individuals and healthy controls with available blood samples and amyloid PET imaging.

Main Results:

• In individuals aged 60+ with CDR ≥0.5, the APS algorithm predicted amyloid PET with 84.9% sensitivity and 96% specificity (excluding inconclusive results).
• A high APS correlated with a greater likelihood of abnormal amyloid plaques and ongoing amyloid accumulation.

Conclusions:

• The study confirms APS as a reliable indicator for predicting brain amyloid plaques.
• Exploratory findings suggest APS may also be effective for screening in cognitively unimpaired individuals, warranting further research.