Plasma Amyloid Concentration in Alzheimer's Disease: Performance of a High-Throughput Amyloid Assay in Distinguishing Alzheimer's Disease Cases from Controls.

ABSTRACT: BACKGROUND:Collection of cerebrospinal fluid (CSF) for measurement of amyloid-? (A?) species is a gold standard in Alzheimer's disease (AD) diagnosis, but has risks. Thus, establishing a low-risk blood A? test with high AD sensitivity and specificity is of outmost interest. OBJECTIVE:We evaluated the ability of a commercially available plasma A? assay to distinguish AD patients from biomarker-healthy controls. METHOD:In a case-control design, we examined plasma samples from 44 AD patients (A?+?N+) and 49 controls (A-N-) from a memory clinic. AD was diagnosed using a combination of neuropsychological examination, CSF biomarker analysis and brain imaging. Total A?40 and total A?42 in plasma were measured through enzyme-linked immunosorbent assay (ELISA) technology using ABtest40 and ABtest42 test kits (Araclon Biotech Ltd.). Receiver operating characteristic (ROC) analyses with outcome AD were performed, and sensitivity and specificity were calculated. RESULTS:Plasma A?42/40 was weakly positively correlated with CSF A?42/40 (Spearman's rho 0.22; p?=?0.037). Plasma A?42/40 alone was not able to statistically significantly distinguish between AD patients and controls (AUC 0.58; 95% CI 0.46, 0.70). At a cut-point of 0.076 maximizing sensitivity and specificity, plasma A?42/40 had a sensitivity of 61.2% and a specificity of 63.6%. CONCLUSION:In this sample, the high-throughput blood A? assay was not able to distinguish well between AD patients and controls. Whether or not the assay may be useful in large-scale epidemiological settings remains to be seen.

SUBMITTER: Feinkohl I 

PROVIDER: S-EPMC7242850 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature