1. |
- Boulo, S., et al.
(författare)
-
First amyloid β1-42 certified reference material for re-calibrating commercial immunoassays
- 2020
-
Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 16:11, s. 1493-1503
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Reference materials based on human cerebrospinal fluid were certified for the mass concentration of amyloid beta (Aβ)1-42 (Aβ42). They are intended to be used to calibrate diagnostic assays for Aβ42. Methods: The three certified reference materials (CRMs), ERM-DA480/IFCC, ERM-DA481/IFCC and ERM-DA482/IFCC, were prepared at three concentration levels and characterized using isotope dilution mass spectrometry methods. Roche, EUROIMMUN, and Fujirebio used the three CRMs to re-calibrate their immunoassays. Results: The certified Aβ42 mass concentrations in ERM-DA480/IFCC, ERM-DA481/IFCC, and ERM-DA482/IFCC are 0.45, 0.72, and 1.22μg/L, respectively, with expanded uncertainties (k=2) of 0.07, 0.11, and 0.18μg/L, respectively. Before re-calibration, a good correlation (Pearson's r>0.97), yet large biases, were observed between results from different commercial assays. After re-calibration the between-assay bias was reduced to<5%. Discussion: The Aβ42 CRMs can ensure the equivalence of results between methods and across platforms for the measurement of Aβ42. © 2020 the Alzheimer's Association
|
|
2. |
- Pannee, Josef, 1979, et al.
(författare)
-
The global Alzheimer's Association round robin study on plasma amyloid beta methods
- 2021
-
Ingår i: Alzheimer's & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction Blood-based assays to measure brain amyloid beta (A beta) deposition are an attractive alternative to the cerebrospinal fluid (CSF)-based assays currently used in clinical settings. In this study, we examined different blood-based assays to measure A beta and how they compare among centers and assays. Methods Aliquots from 81 plasma samples were distributed to 10 participating centers. Seven immunological assays and four mass-spectrometric methods were used to measure plasma A beta concentrations. Results Correlations were weak for A beta 42 while A beta 40 correlations were stronger. The ratio A beta 42/A beta 40 did not improve the correlations and showed weak correlations. Discussion The poor correlations for A beta 42 in plasma might have several potential explanations, such as the high levels of plasma proteins (compared to CSF), sensitivity to pre-analytical sample handling and specificity, and cross-reactivity of different antibodies. Different methods might also measure different pools of plasma A beta 42. We, however, hypothesize that greater correlations might be seen in future studies because many of the methods have been refined during completion of this study.
|
|