Related Experiment Video
Updated: Dec 23, 2025
A Rapid, Multiplex Dual Reporter IgG and IgM SARS-CoV-2 Neutralization Assay for a Multiplexed Bead-Based Flow Analysis System
Published on: April 6, 2021
Analytical performances of a chemiluminescence immunoassay for SARS-CoV-2 IgM/IgG and antibody kinetics
Andrea Padoan1,2, Chiara Cosma1, Laura Sciacovelli1
1Department of Laboratory Medicine, University Hospital of Padova, Padova, Italy.
Insights
This study validates the MAGLUMI 2000 Plus assay for detecting COVID-19 antibodies (IgM and IgG). The assay shows reliable performance and provides insights into antibody kinetics, aiding in COVID-19 diagnosis and management.
Area of Science:
- Clinical Chemistry
- Immunology
- Infectious Diseases
Background:
- Coronavirus disease 2019 (COVID-19) presents a global health challenge with a wide clinical spectrum.
- Diagnostic uncertainty arises from asymptomatic cases and the limitations of current gold-standard tests like real-time reverse transcription polymerase chain reaction (rRT-PCR).
- Measuring specific COVID-19 antibodies (IgM and IgG) offers a complementary, non-invasive diagnostic approach.
Purpose of the Study:
- To analytically validate the MAGLUMI 2000 Plus 2019-nCov IgM and IgG assays.
- To assess the imprecision, linearity, and recovery of the assays.
- To evaluate the time kinetics of IgM and IgG antibody production in COVID-19 patients.
Main Methods:
- Analytical validation using the Clinical and Laboratory Standards Institute (CLSI) EP15-A3 protocol.
- Imprecision and repeatability testing for IgM and IgG assays.
- Dilution, recovery, and immunoglobulin time kinetics studies using patient serum samples.
Main Results:
- The MAGLUMI 2000 Plus assay demonstrated acceptable imprecision and repeatability (<4% for IgM, <6% for IgG).
- Dilution and recovery studies yielded satisfactory results.
- Antibody kinetics showed a rapid increase in IgM and IgG after 6-7 days post-symptom onset, with IgG achieving 100% sensitivity by day 12.
Conclusions:
- The MAGLUMI 2000 Plus assay is valid for measuring specific IgM and IgG antibodies in COVID-19 patients.
- The assay provides valuable data on COVID-19 antibody kinetics.
- These findings support the use of antibody measurements for diagnosing and managing COVID-19.
Abstract:
Background Coronavirus disease 2019, abbreviated to COVID-19, represents an emerging health threat worldwide as, after initial reports in China, it has continued to spread rapidly. The clinical spectrum of the disease varies from mild to severe acute respiratory distress syndrome (ARDS). Moreover, many patients can be asymptomatic, thus increasing the uncertainty of the diagnostic work-up. Laboratory tests play a pivotal role in the diagnosis and management of COVID-19, the current gold standard being real-time reverse transcription polymerase chain reaction (rRT-PCR) on respiratory tract specimens. However, the diagnostic accuracy of rRT-PCR depends on many pre-analytical and analytical variables. The measurement of specific COVID-19 antibodies (both IgG and IgM) should serve as an additional, non-invasive tool for disease detection and management. Methods The imprecision of the MAGLUMI™ 2000 Plus 2019-nCov IgM and IgG assays (Snibe, Shenzhen, China) was assessed by adopting the Clinical and Laboratory Standards Institute (CLSI) EP15-A3 protocol. Linearity of dilution and recovery was evaluated by means of mixes of high-level pools and low-level pools of serum samples. Immunoglobulin time kinetics were evaluated using a series of serum samples, repeatedly collected from COVID-19-positive patients at different times, from <5 days up to 26-30 days. Results Findings at the analytical validation of the assay carried out according to the CLSI EP15-A3 guideline demonstrated that imprecision and repeatability were acceptable (repeatability was <4% and <6% for IgM and IgG, respectively, whilst intermediate imprecision was <6%). In addition, results of dilution and recovery studies were satisfactory. The kinetics of COVID-19 antibodies confirmed previously reported findings, showing a rapid increase of both IgM and IgG after 6-7 days from the symptom onset. IgG had 100% sensitivity on day 12, whilst 88% was the higher positive rate achieved for IgM after the same time interval. Conclusions The findings of this study demonstrate the validity of the MAGLUMI 2000 Plus CLIA assay for the measurement of specific IgM and IgG in sera of COVID-19 patients, and for obtaining valuable data on the kinetics of both (IgM and IgG) COVID-19 antibodies. These data represent a pre-requisite for the appropriate utilization of specific antibodies for the diagnosis and management of COVID-19 patients.
