Cerebrospinal fluid biomarkers measured by Elecsys assays compared to amyloid imaging

• Published in: Alzheimer's & dementia Vol. 14; no. 11; pp. 1460 - 1469
• Main Authors: Schindler, Suzanne E., Gray, Julia D., Gordon, Brian A., Xiong, Chengjie, Batrla-Utermann, Richard, Quan, Marian, Wahl, Simone, Benzinger, Tammie L.S., Holtzman, David M., Morris, John C., Fagan, Anne M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2018
• Subjects: Alzheimer's disease; Amyloid; Biomarker; Cerebrospinal fluid; Cutoff; Biomarker; Amyloid; Cerebrospinal fluid; Alzheimer's disease; Cutoff
• ISSN: 1552-5260; 1552-5279
• DOI: 10.1016/j.jalz.2018.01.013

Levels of amyloid β peptide 42 (Aβ42), total tau, and phosphorylated tau-181 are well-established cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease, but variability in manual plate-based assays has limited their use. We examined the relationship between CSF biomarkers, as measured by a novel automated immunoassay platform, and amyloid positron emission tomography. CSF samples from 200 individuals underwent separate analysis for Aβ42, total tau, and phosphorylated tau-181 with automated Roche Elecsys assays. Aβ40 was measured with a commercial plate-based assay. Positron emission tomography with Pittsburgh Compound B was performed less than 1 year from CSF collection. Ratios of CSF biomarkers (total tau/Aβ42, phosphorylated tau-181/Aβ42, and Aβ42/Aβ40) best discriminated Pittsburgh Compound B–positive from Pittsburgh Compound B–negative individuals. CSF biomarkers and amyloid positron emission tomography reflect different aspects of Alzheimer's disease brain pathology, and therefore, less-than-perfect correspondence is expected. Automated assays are likely to increase the utility of CSF biomarkers. •Cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease were measured with the Roche Elecsys assays.•Total tau/Aβ42, phosphorylated tau-181/Aβ42, and Aβ42/Aβ40 best distinguished Pittsburgh Compound B positron emission tomography status.•All three CSF ratios were positive in 92% of Pittsburgh Compound B–positive individuals.•All three CSF ratios were negative in 81% of Pittsburgh Compound B–negative individuals.•CSF biomarkers may detect Alzheimer's disease pathology earlier than amyloid positron emission tomography.