Detection Of Immunoglobulin M Research Articles

A magnetic-enhanced FRET biosensor for simultaneous detection of multiple antibodies

Accurate, rapid and sensitive detection of specific immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies in human samples is crucial for preventing and assessing pandemics, especially in the case of recent COVID-19 outbreaks. However, simultaneous and efficient detection of IgG and IgM in a single system remains challenging. Herein, we developed a multicolor nanosystem capable of quantitatively analyzing anti-SARS-CoV-2 IgG and IgM with high sensitivity within 20 ​min. The detection system consists of core-shell upconversion nanoparticles (csUCNPs), secondary antibodies labeled with fluorescent dyes (sab), and magnetic nanocrystals (PMF). By leveraging the Förster resonance energy transfer (FRET) effect, the photoluminescence (PL) intensity of blue and green regions is restored for IgG and IgM detection, respectively. Inspiringly, owing to the introducing of PMF, the limits of detection (LODs) of IgG and IgM tested are improved to 89 ​fmol ​L−1 and 19.4 ​fmol ​L−1, representing about 416-folds and 487-folds improvement over only-dye dependent system, respectively. Mechanistic investigations reveal that the high collective effect and surface energy transfer efficiency from csUCNPs to PMF contribute to the enhanced detection sensitivity. The assay enables us to quantify clinical vaccinated samples with high specificity and precision, suggesting our multicolor platform can be a promising alternative for clinical point-of-care serological assay.

Commutability evaluation of candidate reference materials and ERM-DA470k/IFCC for immunoglobulin M using two international approaches.

This study aimed to assess the commutability of frozen pooled human serum (PHS), high concentration of Immunoglobulin M (IgM) pure diluted materials (HPDM), commercialized pure materials (CPM), and dilutions of ERM-DA470k/IFCC in IgM detection using the CLSI and IFCC approaches, to support standardization or harmonization of IgM measurement. Twenty-four serum samples, relevant reference materials (PHS, HPDM, CPM), and different ERM-DA470k/IFCC dilutions were analyzed in triplicate using six routine methods. The commutability of the relevant reference materials was carried out following CLSI EP30-A and IFCC bias analysis. According to the CLSI approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 13, 15, 13, and 8 of 15 assay combinations, respectively. Using the IFCC approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 11, 9, 15, and 10 of 15 assay combinations, respectively. The ERM-DA470k/IFCC dilutions with D-PBS and RPMI-1640 Medium were commutable on 13 of 15 assay combinations according to CLSI and were commutable on all 15 assay combinations using IFCC approach. High concentration of PHS were commutable on all six detection systems using the CLSI approach. Low and medium concentration of PHS showed unsatisfied commutability. HPDM, not CPM have good commutability, has the potential to become reference materials. ERM-DA470k/IFCC diluted with different medium showed different commutability.

Spike- and nucleocapsid-based gold colloid assay toward the development of an adhesive bandage for rapid SARS-CoV-2 immune response detection and screening

Immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies are important biomarkers used for the diagnosis and screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in both symptomatic and asymptomatic individuals. These antibodies are highly specific to the spike (S) and nucleocapsid (N) proteins of the SARS-CoV-2 virus. This paper outlines the development steps of a novel hybrid (vertical-lateral-vertical) flow assay in the form of a finger-stick point-of-care device, similar to an adhesive bandage, designed for the timely detection and screening of IgM and IgG immune responses to SARS-CoV-2 infections. The assay, comprising a vertically stacked plasma/serum separation membrane, conjugate pad, and detection (readout) zone, utilizes gold nanoparticles (AuNPs) conjugated with SARS-CoV-2 S and N proteins to effectively capture IgM and IgG antibodies from a pinprick (~15 µL) of blood in just one step and provides results of no immune IgM−/IgG−, early immune IgM+/IgG−, active immune IgM+/IgG+ or immune IgM−/IgG+ in a short amount of time (minutes). The adhesive bandage-like construction is an example of the design of rapid, low-cost, disposable, and easy-to-use tests for large-scale detection and screening in households. Furthermore, the bandage can be easily adjusted and optimized to detect different viral infections as they arise by simply selecting appropriate antigens related to pandemics and outbreaks.

Epidemiological Parameters of Dengue Infections in Pakistan

Objective: The aim of this research work was to find out epidemiological features associated to age, nature of prevalence, serology and severity of the disease. Methodology: This study was conducted in Benazir Bhutto Hospital; Rawalpindi and the duration of this study was from June 2021 to November 2021. We collected total 149 specimens of sera of the suspected patients appearing with the symptoms of dengue. We analyzed the gathered samples with the help of serological detection of IgM (Immunoglobulin-M), IgG (Immunoglobulin-G), RT-PCR (Reverse transcriptase-Polymerase chain reaction) and culture of virus in CelllineC36/36. Results: Findings of this research work showed that out of total one hundred and forty-nine specimens, 32.20% (n: 48) were identified with dengue virus with the use of RT-PCR & cell culture and 72.50% (n: 108) samples were found positive by serology. Of one hundred and eight cases, 26.80% (n: 48) patients were IgM positive, 41.0% (n: 61) were both IgM & IgG positive and 4.70% (n: 07) patients were IgG positive only. There was very high prevalence of dengue in age-group of patients having 20-29 years of age and the incidence of the infection was much high in male patients as compared to females. There was highest epidemic intensity in month of June as compared to other months. Practical Implication: This current research makes it possible to classify the serological results of dengue by mixed primary-secondary, primary and secondary dengue infections. There is also relation of dengue infection with the season as there is high activity of this infection after season of monsoon Conclusion: The prevalence of dengue is very endemic in our country Pakistan and the most vulnerable age group was 20-29 years for this infection. There is strong need of the effective prevention as well as control measures for the reduction of this infection. Keywords: Infection, serology, dengue, RT-PCR, IgM, epidemiology, IgG, prevention, prevalence, incidence, endemic.

Seroprevalence and Molecular Detection of Symptomatic and Asymptomatic Genital Herpes Simplex Virus 2 among HIV Positive Patients: A Cross-sectional Study

Introduction: Genital Herpes Simplex Virus (HSV) infection is the most common infection in Acquired Immunodeficiency Syndrome (AIDS) patients, occurring in 60-90% according to World Health Organisation (WHO) reports. Early detection of HSV-2 infection, the introduction of chemotherapy, and prophylaxis improve the lifespan of AIDS patients. Aim: To detect the HSV-2 seroprevalence that is Immunoglobulin G (IgG) and Immunoglobulin M (IgM) antibodies in Human Immunodeficiency Virus (HIV) positive serum and molecular detection of HSV-2 Deoxyribonucleic Acid (DNA) in symptomatic HSV-2 Patients. Materials and Methods: The descriptive cross-sectional study was conducted in the Guntur Government Hospital with the help of the Antiretroviral Therapy (ART) Centre and Department of Dermatology, Venereology and Leprosy (DVL) in GGH, Guntur, Andhra Pradesh, India. A total of 100 blood samples from HIV positive individuals were collected and for those with symptoms on the external genitalia, a biopsy specimen from the ulcer and fluid from vesicles were taken. All the cases in the study group are on ART and without any antiviral treatment. A blood sample was collected for IgG (Calbiotech kit), IgM detection (Merilisa kit), and biopsy from genital ulcer for gene detection by realtime Polymerase Chain Reaction (PCR) (HELINI Biomolecules, Chennai). Statistical analysis was done by mean and percentages with p-value by calculating Chi-square test, Fisher’s-Exact test to know significance of association between HSV-2 and HIV. Results: Among the total 100 HIV positive patients, it was observed that IgG seroprevalence of HSV-2 in HIV positive individuals is 78%, while it is 19% for IgM. In the present study, 19 symptomatic cases showed DNA of HSV-2 in PCR, out of which, 17 were from genital ulcers and two from vesicle fluid. Conclusion: As HSV-2 is a lifelong infection, serological testing provides the best method, to estimate its prevalence even in asymptomatic individuals.

Hemolysis-Inspired, Highly Sensitive, Label-Free IgM Detection Using Erythrocyte Membrane-Functionalized Nanomechanical Resonators

Immunoglobulin detection is important for immunoassays, such as diagnosing infectious diseases, evaluating immune status, and determining neutralizing antibody concentrations. However, since most immunoassays rely on labeling methods, there are limitations on determining the limit of detection (LOD) of biosensors. In addition, although the antigen must be immobilized via complex chemical treatment, it is difficult to precisely control the immobilization concentration. This reduces the reproducibility of the biosensor. In this study, we propose a label-free method for antibody detection using microcantilever-based nanomechanical resonators functionalized with erythrocyte membrane (EM). This label-free method focuses on the phenomenon of antibody binding to oligosaccharides (blood type antigen) on the surface of the erythrocyte. We established a method for extracting the EM from erythrocytes and fabricated an EM-functionalized microcantilever (MC), termed EMMC, by surface-coating EM layers on the MC. When the EMMC was treated with immunoglobulin M (IgM), the bioassay was successfully performed in the linear range from 2.2 pM to 22 nM, and the LOD was 2.0 pM. The EMMC also exhibited excellent selectivity compared to other biomolecules such as serum albumin, γ-globulin, and IgM with different paratopes. These results demonstrate that EMMC-based nanotechnology may be utilized in criminal investigations to identify blood types with minimal amounts of blood or to evaluate individual immunity through virus-neutralizing antibody detection.

Immunoglobulin M seroneutralization for improved confirmation of Japanese encephalitis virus infection in a flavivirus-endemic area.

The mainstay of diagnostic confirmation of acute Japanese encephalitis (JE) involves detection of anti-JE virus (JEV) immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA). Limitations in the specificity of this test are increasingly apparent with the introduction of JEV vaccinations and the endemicity of other cross-reactive flaviviruses. Virus neutralization testing (VNT) is considered the gold standard, but it is challenging to implement and interpret. We performed a pilot study to assess IgG depletion prior to VNT for detection of anti-JEV IgM neutralizing antibodies (IgM-VNT) as compared with standard VNT. We evaluated IgM-VNT in paired sera from anti-JEV IgM ELISA-positive patients (JE n=35) and negative controls of healthy flavivirus-naïve (n=10) as well as confirmed dengue (n=12) and Zika virus (n=4) patient sera. IgM-VNT was subsequently performed on single sera from additional JE patients (n=76). Anti-JEV IgG was detectable in admission serum of 58% of JE patients. The positive, negative and overall percentage agreement of IgM-VNT as compared with standard VNT was 100%. A total of 12/14 (86%) patient samples were unclassified by VNT and, with sufficient sample available for IgG depletion and IgG ELISA confirming depletion, were classified by IgM-VNT. IgM-VNT enabled JE case classification in 72/76 (95%) patients for whom only a single sample was available. The novel approach has been readily adapted for high-throughput testing of single patient samples and it holds promise for incorporation into algorithms for use in reference centres.

Evaluation of Performance of Detection of Immunoglobulin G and Immunoglobulin M Antibody Against Spike Protein of SARS-CoV-2 by a Rapid Kit in a Real-Life Hospital Setting.

BackgroundAntibody testing is often used for serosurveillance of coronavirus disease 2019 (COVID-19). Enzyme-linked immunosorbent assay and chemiluminescence-based antibody tests are quite sensitive and specific for such serological testing. Rapid antibody tests against different antigens are developed and effectively used for this purpose. However, their diagnostic efficiency, especially in real-life hospital setting, needs to be evaluated. Thus, the present study was conducted in a dedicated COVID-19 hospital in New Delhi, India, to evaluate the diagnostic efficacy of a rapid antibody kit against the receptor-binding domain (RBD) of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).MethodsSixty COVID-19 confirmed cases by reverse transcriptase–polymerase chain reaction (RT-PCR) were recruited and categorized as early, intermediate, and late cases based on the days passed after their first RT-PCR–positive test report, with 20 subjects in each category. Twenty samples from pre-COVID era and 20 RT-PCR–negative collected during the study period were taken as controls. immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies against the RBD of the spike (S) protein of SARS-CoV-2 virus were detected by rapid antibody test and compared with the total antibody against the nucleocapsid (N) antigen of SARS-CoV-2 by electrochemiluminescence-based immunoassay (ECLIA).ResultsThe detection of IgM against the RBD of the spike protein by rapid kit was less sensitive and less specific for the diagnosis of SARS-CoV-2 infection. However, diagnostic efficacy of IgG by rapid kit was highly sensitive and specific when compared with the total antibody against N antigen measured by ECLIA.ConclusionIt can be concluded that detection of IgM against the RBD of S protein by rapid kit is less effective, but IgG detection can be used as an effective diagnostic tool for SARS-CoV-2 infection in real-life hospital setting.

SPEEDS: A portable serological testing platform for rapid electrochemical detection of SARS-CoV-2 antibodies

The COVID-19 pandemic has resulted in a worldwide health crisis. Rapid diagnosis, new therapeutics and effective vaccines will all be required to stop the spread of COVID-19. Quantitative evaluation of serum antibody levels against the SARS-CoV-2 virus provides a means of monitoring a patient's immune response to a natural viral infection or vaccination, as well as evidence of a prior infection. In this paper, a portable and low-cost electrochemical immunosensor is developed for the rapid and accurate quantification of SARS-CoV-2 serum antibodies. The immunosensor is capable of quantifying the concentrations of immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies against the SARS-CoV-2 spike protein in human serum. For IgG and IgM, it provides measurements in the range of 10.1 ng/mL − 60 μg/mL and 1.64 ng/mL − 50 μg/mL, respectively, both with an assay time of 13 min. We also developed device stabilization and storage strategies to achieve stable performance of the immunosensor over 24-week storage at room temperature. We evaluated the performance of the immunosensor using COVID-19 patient serum samples collected at different time points after symptom onset. The rapid and sensitive detection of IgG and IgM provided by our immunosensor fulfills the need of rapid COVID-19 serological testing for both point-of-care diagnosis and population immunity screening.

Electrochemical Biosensor with Enhanced Antifouling Capability Based on Amyloid-like Bovine Serum Albumin and a Conducting Polymer for Ultrasensitive Detection of Proteins in Human Serum.

Biofouling has been a substantial burden on biomarker analysis in complex biological media, leading to poor sensitivity and selectivity or even malfunction of the sensing devices. In this work, an electrochemical biosensor with excellent antifouling ability and high stability was fabricated based on amyloid-like bovine serum albumin (AL-BSA) crosslinked with the conducting polymer polyaniline (PANI). Compared with the crosslinked conventional bovine serum albumin (BSA), the crosslinked AL-BSA exhibited enhanced antifouling capability, and it was able to form an effective antifouling film within a significantly short reaction time. With further immobilization of immunoglobulin M (IgM) antibodies onto the prepared AL-BSA surface via the formation of amide bonds, an electrochemical biosensor capable of assaying IgM in human serum samples with superior selectivity and sensitivity was constructed. The biosensor exhibited excellent antifouling performance even in 100% human serum, a low limit of detection down to 2.32 pg mL-1, and acceptable accuracy for real sample analysis compared with the standard enzyme-linked immunosorbent assay for IgM detection. This strategy of using AL-BSA to construct antifouling sensing interfaces provided a reliable diagnostic method for the detection of a series of protein biomarkers in complex biological media.

Surface Plasmon Resonance-Based Immunosensor for Igm Detection with Gold Nanoparticles.

In this work, a surface plasmon resonance (SPR) based immunosensor was prepared by the immobilization of the amine-functionalized gold nanoparticles (N-AuNPs) on the sensing surface to sense immunoglobulin M (IgM) antibodies in the aqueous solution and artificial plasma. The characterization studies of SPR based immunosensor for IgM detection were performed with scanning electron microscope (SEM), contact angle measurements, and ellipsometry. Kinetic studies for the IgM immunosensor were carried out in the range of 1.0 to 200 ng/mL IgM concentrations in an aqueous solution. The total IgM analysis time including adsorption, desorption, and regeneration cycles was nearly 10 min for the prepared immunosensor. The limit of detection (LOD) and limit of quantification (LOQ) were found as 0.08 and 0.26 ng/mL, respectively. The reusability of the proposed immunosensor was tested with 6 consecutive adsorption-desorption, and regeneration cycles. Also, enzyme-linked immunosorbent assay (ELISA) method was utilized in the validation of the immunosensor.

Hepatitis E Virus Immunoglobulin M (IgM) and associated risk factors in southwest, Nigeria

Hepatitis E is one of the most frequent causes of acute hepatitis worldwide, with an estimated 20 million infections and 70,000 deaths attributed to hepatitis E virus (HEV) genotypes 1 and 2 every year. This study was designed to determine the prevalence of HEV immunoglobulin M (IgM) in southwest (SW) Nigeria. Venous blood samples totalling 359 were collected from pregnant women on routine check, apparently healthy prospective blood donors and sick individuals presenting with fever and abdominal disturbance from health facilities in Ekiti, Lagos, Osun and Oyo states, of Nigeria. A structured questionnaire form was administered to gather socio-demographic data, health and travel history from each consenting participant. The screening for HEV IgM was done using HEV IgM ELISA kit. Statistical analyses, including descriptive analysis, correlations and binary logistic regression were carried out using SPSS version 21. In all, 131 samples (36.5%) tested positive for HEV IgM. Osun state had the highest occurrence of HEV IgM (n = 49; 13.6%,) while Ekiti had the least (n= 22; 6.1%). Apparently healthy participants with detectable HEV IgM were 52 (14.5%) while pregnant womenwere 51 (14.2%). Risk factors implicated in this study were flooding and injection drug use. The overall HEV prevalence reported in this study was higher than previous reports in Nigeria . Higher HEV prevalence in this study could be due to a larger coverage area in the country as well as detection of ongoing infection. The detection of HEV IgM in pregnant women and apparently healthy prospective blood donors indicated ongoing infection with risk of spread to susceptibles since HEV is neither routinely screened for among pregnant women nor among prospective blood donors.
 Keywords: Hepatitis E, IgM, Pregnancy, Apparently healthy, ELISA Depth, Geothermal Energy

Early Detection of SARS-CoV-2 Seroconversion in Humans with Aggregation-Induced Near-Infrared Emission Nanoparticle-Labeled Lateral Flow Immunoassay.

An outbreak of coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses great threats to human health and the international economy. To reduce large-scale infection and transmission risk of SARS-CoV-2, a simple, rapid, and sensitive serological diagnostic method is urgently needed. Herein, an aggregation-induced emission (AIE) nanoparticle (AIE810NP, λem = 810 nm)-labeled lateral flow immunoassay was designed for early detection of immunoglobulin M (IgM) and immunoglobulin G (IgG) against SARS-CoV-2 in clinical serum samples. Using a near-infrared (NIR) AIE nanoparticle as the fluorescent reporter (△λ = 145 nm), the autofluorescence from the nitrocellulose membrane and biosample and the excitation background noise were effectively eliminated. After optimization, the limit of detection of IgM and IgG is 0.236 and 0.125 μg mL–1, respectively, commensurate with that of the enzyme-linked immunosorbent assay (ELISA) (0.040 and 0.039 μg mL–1). The sensitivity of the proposed AIE810NP-based test strip for detecting IgM and IgG is 78 and 95% (172 serum samples), commensurate with that of ELISA (85 and 95%) and better than that of a commercial colloidal gold nanoparticle (AuNP)-based test strip (41 and 85%). Importantly, the time of detecting IgM or IgG with an AIE810NP-based test strip in sequential clinical samples is 1–7 days after symptom onset, which is significantly earlier than that with a AuNP-based test strip (8–15 days). Therefore, the NIR-emissive AIE nanoparticle-labeled lateral flow immunoassay holds great potential for early detection of IgM and IgG in a seroconversion window period.

Detection of IgM, IgG and SARS-CoV-2 RNA among the personnel of the University of Milan, March through May 2020: the UNICORN study

ObjectivesIn Italy, the pandemic of COVID-19 resulted in congestion of hospitals and laboratories and probably determined an underestimation of the number of infected subjects, as the molecular diagnosis of SARS-CoV-2...

Anti-SARS-CoV-2 IgG and IgM detection with a GMR based LFIA system

Since December 2019, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused millions of deaths and seriously threatened the safety of human life; indeed, this situation is worsening and many people are infected with the new coronavirus every day. Therefore, it is very important to understand patients’ degree of infection and infection history through antibody testing. Such information is useful also for the government and hospitals to formulate reasonable prevention policies and treatment plans. In this paper, we develop a lateral flow immunoassay (LFIA) method based on superparamagnetic nanoparticles (SMNPs) and a giant magnetoresistance (GMR) sensing system for the simultaneously quantitative detection of anti-SARS-CoV-2 immunoglobulin M (IgM) and G (IgG). A simple and time-effective co-precipitation method was utilized to prepare the SMNPs, which have good dispersibility and magnetic property, with an average diameter of 68 nm. The Internet of Medical Things-supported GMR could transmit medical data to a smartphone through the Bluetooth protocol, making patient information available for medical staff. The proposed GMR system, based on SMNP-supported LFIA, has an outstanding advantage in cost-effectiveness and time-efficiency, and is easy to operate. We believe that the suggested GMR based LFIA system will be very useful for medical staff to analyze and to preserve as a record of infection in COVID-19 patients.

Paper-Based Microfluidic Devices: Low-Cost Platforms for Rapid Biochemical Detection.

We developed low-cost, portable paper-based diagnostic devices for detection of human immunoglobulin M (IgM) and immunoglobulin G (IgG) in serum without any sample preparation. These devices can be used to help identify presence of diseases, used to provide rapid results (<5 minutes), readily used by untrained personnel, employed in austere environments, configured to obtain multiplexed assays, and easily disposed of. We successfully accomplished colorimetric detection of human IgG and human IgM using a sandwich-style assay within the microfluidic paper device via vertical flow immunoassay configuration. The reaction zone in the wax printed paper layer is a small circular pattern. Gold nanoparticles conjugated with anti-human IgG and IgM antibodies have been used for colorimetric detection of IgG or IgM by naked eye. Colorimetric signal can be precisely quantified through implementation of image analysis software which can be developed as an app for a smartphone. The size of the device is 2 cm × 2 cm × 1 mm. Colorimetric detection of human IgG was accomplished at 100 fg/mL concentration using a gold nanoparticle-conjugated anti-human IgG antibody. The developed platform has a dynamic range of IgM and IgG concentrations between 0.1 pg/mL and 100 μg/mL. These devices provided a color readout in <5 minutes using 20 µL of serum. We also demonstrated that the devices show a significant degree of ruggedness and temperature stability as they were able to provide satisfactory results (detection of 0.1 pg/mL IgG) after 14 days of long stability and shelf-life experiment at an elevated temperature of at least 50 ˚C-the shelf life can be as long as 180 days under ambient conditions for detection of 100 µg/mL IgG. Because of the inherent simplicity of the device operation and their ease of use, there is no variation between samples and users of the device. This low-cost approach enables multiplexing with >1 measurement performed in parallel at the same time. We anticipate that because of the sensitivity, specificity, ease of use, and overall reliability, this approach will become a standard for diagnosis of diseases and health conditions.

Detection of Immunoglobulin G (IgG) and Immunoglobulin M (IgM) Antibodies Using Circular Photonic Crystal Fiber Sensor

In this paper, a circular Photonic Crystal fiber (C-PCF) is designed to detect two types of antibodies such as Immunoglobulin G (IgG) and Immunoglobulin M (IgM). Light guiding property of different refractive index (RI) of IgG and IgM are analyzed. For various RI value confinement losses, relative sensitivity and effective mode area are analyzed. The projected C-PCF sensor produces low confinement loss and high sensitivity for the detection of IgM and IgG. Realistic execution of the proposed PCF sensor is viable by accessible technology and it is applicable to sense corona virus disease.

Dynamic changes of IgM and IgG in confirmed COVID-19 cases: detection results analysis

Objective  To analyze dynamic changes of immunoglobulin M (IgM) and immunoglobulin G (IgG) in 49 confirmed cases of coronavirus disease 2019 (COVID-19) during various periods of the disease and to explore regulations and characteristics of antibodies production against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for providing evidences for effective prevention and control of COVID-19 epidemic. Methods  Totally 114 blood samples were collected from 49 viral nucleic acid detection-confirmed COVID-19 patients (one sample for 17 cases and 2 – 7 samples for 32 cases) and blood samples from another 49 viral nucleic acid negative cases were also collected as controls in Changde city, Hunan province between January 24 and February 22, 2020. Fluorescent immunochromatography was used to detect serum SARS-CoV-2 IgM and IgG and dynamic changes in IgM and IgG were statistically analyzed. Results  Of the 114 serum specimens from 49 viral nucleic acid positive cases, 96 (84.21%) were IgM positive and 108 (94.74%) were IgG positive, with a significant difference between the two positive rates (P Conclusion  The detection of IgM and IgG is an effective supplement to the nucleic acid tesing for COVID-19. The dynamic monitoring of SARS-CoV-2 IgM and IgG antibody are of significance for COVID-19-related epidemiological survey, therapeutic effect evaluation, and vaccine development.

Highlighted Prospects of an IgM/IgG Antibodies Test in Identifying Individuals With Asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection.

Covert severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections could be seeding new outbreaks. How to identify asymptomatic SARS-CoV-2 infections early has become a global focus. To explore the roles of immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies detection, nucleic acid tests, and computed tomography (CT) scanning to identify asymptomatic SARS-CoV-2 infection. The clinical data of 389 individuals with close contacts, including in general characteristics, SARS-CoV-2 etiology, serum-specific IgM and IgG antibody detection and CT imaging results, were systematically analyzed. The present study showed that only 89 of 389 individuals with close contacts were positive after the first nucleic acid test, while 300 individuals were still negative after 2 nucleic acid tests. Among the 300 individuals, 75 did not have pneumonia, and the other 225 individuals had pulmonary imaging changes. A total of 143 individuals were eventually diagnosed as having asymptomatic infection through IgM antibody and IgG antibody detection. The sensitivity, specificity, and false-negative rate of IgM and IgG antibody detection were approximately 97.1% (347 of 357), 95.3% (204 of 214), and 4.67% (10 of 214), respectively. It also indicated that during approximately 2 weeks, most individuals were both IgM positive and IgG positive, accounting for 68.57% (72 of 105). During approximately 3 weeks, the proportion of IgM-positive and IgG-positive individuals decreased to 8.57% (9 of 105), and the proportion of IgM-negative and IgG-positive individuals increased to 76.19% (80 of 105). There are highlighted prospects of IgM/IgG antibody detection as a preferred method in identifying the individuals with asymptomatic SARS-CoV-2 infection, especially combined with nucleic acid tests and pulmonary CT scanning.

Diagnostic performance of immunochromatography assay for rapid detection of IgM and IgG in coronavirus disease 2019

Serologic assays have been developed to detect infection with coronavirus disease 2019 (COVID‐19). This study was conducted to evaluate the diagnostic performance of an immunochromatography‐based assay of human serum for COVID‐19. The present study enrolled 149 subjects who had been tested by real‐time reverse transcription‐polymerase chain reaction (RT‐PCR) for COVID‐19 and were classified into two groups: 70 who were positive for COVID‐19 and 79 who were negative for COVID‐19 based on RT‐PCR. An immunochromatography‐based COVID‐19 immunoglobulin G (IgG)/immunoglobulin M (IgM) rapid test on the sera of the study population was applied to measure the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic (ROC) curve compared to RT‐PCR, with a 95% confidence interval (CI). IgM or IgG antibodies were detected in 65 subjects (92.9%) classified as positive for COVID‐19 and in three subjects (3.8%) classified as negative for COVID‐19. The sensitivity and specificity percentages for IgM or IgG antibodies were 92.9% (95% CI: 84.1‐97.6) and 96.2% (95% CI: 89.3‐99.2), respectively, with 95.6% PPV and 93.8% NPV. The PPV rapidly improved with increasing disease prevalence from 19.8% to 96.1% in the presence of either IgM or IgG, while the NPV remained high with a change from 99.9% to 93.1%. The area under the ROC curve was 0.945 (95% CI: 0.903‐0.988) for subjects with either IgM or IgG positivity. In conclusion, the immunochromatography‐based COVID‐19 IgG/IgM rapid test is a useful and practical diagnostic assay for detection of COVID‐19, especially in the presence of IgM or IgG antibodies.