Journal Article

Plasma amyloid assay as a pre-screening tool for amyloid positron emission tomography imaging in early stage Alzheimer’s disease

Huang, Chin-Chang, Yen, Tzu-Chen, Lin, Szu-Ying, Chang, Chiung-Chih, Huang, Wen-Sheng, Lee, Yi-Chung, Hsiao, Ing-Tsung, Yang, Bang-Hung, Wang, Pei-Ning, Lin, Kun-Ju, Lin, Po-Chen

2019

Overview

Introduction Due to the high cost and high failure rate of ascertaining amyloid positron emission tomography positivity (PET+) in patients with earlier stage Alzheimer’s disease (AD), an effective pre-screening tool for amyloid PET scans is needed. Methods Patients with mild cognitive impairment ( n  = 33, 24.2% PET+, 42% females, age 74.4 ± 7.5, MMSE 26.8 ± 1.9) and mild dementia ( n  = 19, 63.6% PET+, 36.3% females, age 73.0 ± 9.3, MMSE 22.6 ± 2.0) were recruited. Amyloid PET imaging, Apolipoprotein E ( APOE ) genotyping, and plasma amyloid β (Aβ) 1–40 , Aβ 1–42 , and total tau protein quantification by immunomagnetic reduction (IMR) method were performed. Receiver operating characteristics (ROC) analysis and Youden’s index were performed to identify possible cut-off points, clinical sensitivities/specificities, and areas under the curve (AUCs). Results Amyloid PET+ participants had lower plasma Aβ 1–42 levels than amyloid PET-negative (PET−) subjects. APOE ε4 carriers had higher plasma Aβ 1–42 than non-carriers. We developed an algorithm involving the combination of plasma Aβ 1–42 and APOE genotyping. The success rate for detecting amyloid PET+ patients effectively increased from 42.3 to 70.4% among clinically suspected MCI and mild dementia patients. Conclusions Our results demonstrate the possibility of utilizing APOE genotypes in combination with plasma Aβ 1–42 levels as a pre-screening tool for predicting the positivity of amyloid PET findings in early stage dementia patients.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Accuracy / Advertising executives / Algorithms / Alzheimer's disease / Amyloid PET / APOE / Apolipoproteins / Biological markers / Biomarkers / Biomedical and Life Sciences / Biomedicine / Brain / Cognitive ability / Dementia / Diagnostic imaging / Disease / EDTA / Florbetapir / Genotypes / Geriatric Psychiatry / Geriatrics/Gerontology / Laboratories / MCI / Medical imaging / Medical research / Medical tests / Neurology / Neurosciences / Pathology / Plasma Aβ / Positron emission tomography / Proteins / Tomography