Amyloid β 1-42 IMR Reagent

“MagQu” Amyloid β 1-42 IMR Reagent is designed for quantitative measurement of Tau protein concentration in human plasma by immunomagnetic reduction (IMR) assay. The reagent can be used with MagQu’s Magnetic Immunoassay Analyzer XacPro-S system.
This assay enables early-stage neurological disease research with ultra-high sensitivity and low interference.

Features

Ultra sensitivity
Low interference
Easy operation
Diagnosis of
- Alzheimer’s Disease (AD)
- Mild cognitive impairment (MCI)
- Down’s syndrome

Specifications

Sample type: Human Plasma

Sample volume: 60 μl

Assay time: 5 hours (36 channels in XacPro-S)

Use application: In vitro diagnostic

Detection methods: ImmunoMagnetic Reduction (by analyzer XacPro-S with magnetic reagents)

Sensitivity

Detection Range: 1 - 100 pg/ml

Low detection limit: 80 fg/ml

Line graph showing the relationship between AB42 (pg/ml) and IMR (%) with an increasing trend.

IMR standard curve of Aβ1-42

Description

Intended Use

“MagQu” Amyloid β 1-42 IMR Reagent is used to quantitatively measure Aβ1-42 protein in human fluid specimen, such as plasma.

Use “MagQu” Amyloid β 1-42 IMR Reagent only with the XacPro-S System (MagQu Co., Ltd.).

Introduction

Amyloid β (Aβ or Abeta) denotes peptides of 36–43 amino acids that are crucially involved in Alzheimer's disease as the main component of the amyloid plaques found in the brains of Alzheimer patients. The peptides result from the amyloid precursor protein (APP), which is being cut by certain enzymes to yield Aβ. One of the most common isoforms is Aβ1-42.1,2

Principles of Test

“MagQu” Amyloid β 1-42 IMR Reagent is designed for rapid quantifying Aβ1-42 protein by Immuno Magnetic Reduction (IMR). We conjugated the antibody on the surface of around 50 nm-in-diameter Fe3O4 magnetic particles. When the antibodies on the surface bind with Aβ1-42 protein, the magnetic particles form clusters. Therefore, the ac susceptibility (Xac) of magnetic particles would be reduced in the adding ac magnetic field. By measuring the reduction of Xac, we can quantify Tau protein in the sample easily, rapidly, and accurately.3

Reagent Properties

Property	Detail
Core	Iron Oxide (Fe₃O₄)
Layer	Dextran
Surface Protein	Anti-Aβ_1-42 antibody
Mean Diameter of Particles	50 - 60 nm
Analytical Range	1 to 100 pg/mL Aβ_1-42 protein for clinical samples
Buffer	pH 7.4 PBS
Storage Temperature	2 - 8 °C

Precision

The Aβ1-42 samples were measured in duplicate,

twice per day over 20 days. Two different Aβ1-42

concentrations were used for the tests.

The standard deviations of repeatability and with-

in-lab for various Aβ1-42 concentrations ware

obtained.

Interference (Specificity)

Plasma can contain interfering substances such as hemo-

globin, bilirubin, or intra lipid because of common

diseases, such as hemolysis, jaundice or hypertriglyceri-

demia. Other bio-substances that exist naturally in plasma,

such as uric acid, rheumatoid factor, or albumin, are also

interfering substances.

Other interfering substances include drugs or chemicals in

medicine that is used to treat inflammatory diseases, viral

and bacterial infections, cancers and cardiovascular

disease. The level of Aβ1-42 in each of these pools was

then determined and normalized to the level without the

respective substances.

Expected Value

Fig 1:IMR and ELISA were applied to assay Aβ42 in plasma and CSF, respectively. A moderately negative correlation between plasma and CSF Aβ42 levels in AD patients (r = –0.352), and a weakly positive correlation in controls (r = 0.186). (refer to reference 1)

Scatter plot showing plasma Aβ42 levels versus CSF Aβ42 levels with data points for control and Alzheimer's disease groups, including a fitted curve and a table with group statistics.

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Item tested	Mean of measured Aβ 1-42 concentrations (pg/ml)	Standard deviation (%CV)
Item tested	Mean of measured Aβ 1-42 concentrations (pg/ml)	Repeatability	Within-Lab
pool 1	10.07	0.77 (7.6)	0.82 (8.2)
pool 2	101.67	5.20 (5.1)	6.76 (6.7)

Precision testing was determined according to CLSI/NCCLs document EP5-A3.

Substance	Amount Added	% Recovery (Spike/control × 100)
Hemoglobin	10000 µg/ml	97.7
Conjugated bilirubin	600 µg/ml	98.0
Intra lipid	30000 µg/ml	100.3
Uric acid	200 µg/ml	101.2
Rheumatoid factor	500 IU/ml	98.7
Albumin	60000 µg/ml	94.1
Acetylsalicylic acid	500 µg/ml	100.7
Ascorbic acid	300 µg/ml	98.8
Ampicillin sodium	1000 µg/ml	102.3
Quetiapine fumarate	100 ng/ml	98.4
Galantamine hydrobromide	90 ng/ml	95.4
Rivastigmine hydrogen tartrate	100 ng/ml	96.0
Donepezil hydrochloride	1000 ng/ml	100.5
Memantine hydrochloride	150 ng/ml	99.8
Amyloid β 1-40	100 pg/ml	99.6
Total Tau protein	100 pg/ml	93.6
Human Anti-Mouse Antibody (HAMA)	100 ng/ml	93.5

Interference testing was based on the principle of CLSI/NCCLs document EP7-A2.

Fig 2: Fig.2 (a) Concentration products of Aβ-42 and tau protein in plasma from different clinical groups, detected using immunomagnetic reduction, and the ROC curves to distinguish (b) the healthy control group from t he patient group (combining MCI due to AD, very mild AD, and mild-to-severe AD dementia) and to distinguish (c) the MCI due to AD and the AD dementia groups. (refer to reference 2).

Two scatter plots and two ROC curves displaying medical data related to tau protein levels across different conditions, such as healthy control, MCI, very mild AD, and mild-to-severe AD.

Application References:

1. Fan Ling-Yun et al., “The Relation Between Brain Amyloid Deposition, Cortical Atrophy, and Plasma Biomarkers in Amnesic Mild Cognitive Impairment and Alzheimer’s Disease” Front. Aging Neurosci. 2018; 10:175.

2. Chiu Ming-Jang et al. “Combined plasma biomarkers for diagnosing mild cognition impairment and Alzheimer's disease” ACS chemical neuroscience. 2013; 4:1530.