Brucellosis relapse seven years after first infection in a COVID-19 patient: A case report

Coronavirus disease 2019 (COVID-19) emerged in China and then has spread worldwide. It has been seen in Turkey since March. Brucellosis is a zoonotic disease which is observed in Turkey endemically. Here, we report the firstcase of Brucellosis relapse in a COVID-19 patient. A 39-year-old female had cough, dispnea, fatigue and backpain and miyalgia for one week was admitted. She had leucopenia and lymphopenia in whole blood count. She had a contact history with her COVID-19 positive sister. COVID-19 polymerase chain reaction (PCR) test resulted positive. She received hydroxychloroquine treatment for five days. Her COVID-19 PCR became negative and laboratory improved. Her miyalgia, back pain and fatigue got worse. When her medical history was elaborated, she had a brucellosis history seven years ago. She was completely treated and her Brucella serology tests were negative in 2015. She stated that she didn't consume any unpasteurized milk product recently. Rose-Bengal and Coombs agglutination tests were positive (1:320 titers). She was initialized on treatment and symptoms started to resolve after 15 days of treatment. Severe COVID-19 patients show lymphopenia, particularly reduction of T-cells. Cell mediated immunity is crucial against brucellosis. During pandemic, endemic infections like brucellosis can be observed in patients due to lymphopenia. Further immunological studies are needed.Copyright © 2022, Kuwait Medical Association. All rights reserved.

Use of the particle agglutination/particle agglutination inhibition test for antigenic analysis of SARS-CoV-2.

Background: The antigenicity of SARS-CoV-2 is a critical issue for the effectiveness of the vaccine, and thus, it should be phenotypically evaluated by serological assays as new field isolates emerge. The hemagglutination/hemagglutination inhibition (HA/HI) tests are well known as a representative method for antigenic analysis of influenza viruses, but SARS-CoV-2 does not agglutinate human or guinea pig red blood cells. Therefore, the antigenic analysis requires complicated cell-based assays using special equipment such as plate reader or ELISPOT analyzer. Methods: Based on the HA/HI tests for influenza viruses, we developed the particle agglutination/particle agglutination inhibition (PA/PAI) test to easily and rapidly quantify the virus and antibody using human angiotensin-converting enzyme 2 (hACE2)-bound latex beads. The virus titers were determined by mixing the beads and the virus from culture supernatant, settling it overnight, and then observing the sedimentation/agglutination pattern (PA test). The neutralization antibody titers were determined by mixing virus-infected hamster antisera in addition to the beads and virus (PAI test). Results: The PA titer was positively correlated with the plaque-forming units. The PAI titer using the hamster antisera clearly revealed the antigenic difference between the omicron and previous variants. The antigenic differences were supported by the results shown in other methods. Conclusions: The PAI test is an easy and rapid method to analyze the antigenicity of SARS-CoV-2.

Amyloid peptides with antimicrobial and/or microbial agglutination activity.

Microbe (including bacteria, fungi, and virus) infection in brains is associated with amyloid fibril deposit and neurodegeneration. Increasing findings suggest that amyloid proteins, like Abeta (Aß), are important innate immune effectors in preventing infections. In some previous studies, amyloid peptides have been linked to antimicrobial peptides due to their common mechanisms in membrane-disruption ability, while the other mechanisms of bactericidal protein aggregation and protein function knockdown are less discussed. Besides, another important function of amyloid peptides in pathogen agglutination is rarely illustrated. In this review, we summarized and divided the different roles and mechanisms of amyloid peptides against microbes in antimicrobial activity and microbe agglutination activity. Besides, the range of amyloids' antimicrobial spectrum, the effectiveness of amyloid peptide states (monomers, oligomers, and fibrils), and cytotoxicity are discussed. The good properties of amyloid peptides against microbes might provide implications for the development of novel antimicrobial drug. KEY POINTS: • Antimicrobial and/or microbial agglutination is a characteristic of amyloid peptides. • Various mechanisms of amyloid peptides against microbes are discovered recently. • Amyloid peptides might be developed into novel antimicrobial drugs.

Study on quantitative detection of bacterial endotoxin in recombinant novel coronavirus vaccine (CHO cell) by micro-dynamic chromogenic

Aim To explore the feasibility of the micro- dynamic chromogenic method for quantitative detection of bacterial endotoxin in recombinant novel coronavirus vaccine ( CHO cell).Methods The micro-dynamic color method of Limulus reagent was used to establish a bacterial endotoxin standard curve.The dilution factor was determined through interference pre -experiment, the recoverv rate of the endotoxin added to the test so- J lution was determined, and the interference test to complete the quantitative detection test of the bacterial endotoxin content in the test product was performed, and the results were compared with those of the gel-clot method.Results Hie linear range of the concentration of the standard curve was 0.02 to 2.0 EU * mL 1 , and the regression equation of the standard curve was lgT =-0.302 7 lgC +2.858 7( r = 0.998 9).When recombinant novel coronavirus vaccine ( CHO cell) was cliluted 40 times or below, the micro -dynamic chromogenic reagent did not interfere with the bacterial endotoxin agglutination reaction, and the recovery rate was 50% to 200%.The test results were consistent with the gel- clot method.Conclusions The micro-dynamic chromogenic method can be used for the quantitative detection of bacterial endotoxins in recombinant novel coronavirus vaccine ( CHO cell) with accurate results, high sensitivity, and process monitoring. Copyright © 2022 Publication Centre of Anhui Medical University. All rights reserved.

Evaluating of the egyptian knowledge, awareness and applications of infection control strategies toward coronavirus (Covid-19)

Introduction: A novel human coronavirus is now called COVID-19 virus had not been detected before. The outbreak reported in Wuhan, China, in December 2019. Aim of the study: To evaluate the Egyptians' knowledge, awareness and applications of infection control strategies toward coronavirus (COVID-19). Material(s) and Method(s): A prospective study has conducted to evaluate the Egyptians' knowledge, awareness, and applications of strategies toward infection control of coronavirus (COVID-19). An electronic sheet consists of three parts was developed for gathering information about their socio-demographic data, their information about COVID-19, and their applications toward COVID-19 infection control. Result(s): The study results confirm that Egyptian had a satisfactory level of the overall knowledge about the nature of COVID-19 including causative agent, and signs of the disease while had bad of knowledge regarding rates of coronavirus transmission. Concerning their applications of infection control strategies, they reported good applications. Recommendations: Egyptian need more education about mode of transmissions and the scientific strategies for prevent of COVID-19 virus spread. Copyright © 2020 Japan Health Sciences University & Japan International Cultural Exchange Foundation.

Secretory immunoglobulin A of the respiratory system and COVID-19

The main focus in the course of COVID-19 goes on assessing the overall immune response. The role of mucosal immunity in this disease has not been studied sufficiently. The study aimed to analyze published data about secretory IgA as a significant indicator of the mucosal immune response of the respiratory tract in the context of the COVID-19 pandemic. Methods. Articles were identified via PubMed bibliographic database. The time-span of research was two years (2020, 2021). Results. The search identified 54 articles. There is evidence that secretory IgA (sIgA) is the main antibody isotype of the mucosal immunity. It is produced in quantities significantly higher than those of all other isotypes of immunoglobulins combined. sIgA antibodies are effective against various pathogens, including the SARS-CoV-2 virus, due to mechanisms such as neutralization, suppression of adhesion to the mucosal surface and invasion of epithelial cells, agglutination and facilitating the removal of pathogenic microorganisms with the mucosal secretions. Virus-specific IgA antibodies in the blood serum are detected in patients with COVID-19 as early as two days after the first symptoms, while IgM or IgG class antibodies appear only after 5 days. We accessed the efficacy of intranasal immunization as to induction of predominant production of sIgA in the upper and lower respiratory tract. Conclusion. The current information on the local immune response of the respiratory mucosa is important for understanding the pathophysiological mechanisms of the disease, diagnosis, and development of new methods of treatment and prevention of COVID-19.

Cycling profiles of unconfirmed syphilis repeat-reactive serology results during influenza and COVID-19 vaccination campaigns: September 2017-January 2022

Background: All donations at Canadian Blood Services (CBS) are screened for syphilis using a serology screening and confirmation test algorithm. Currently, syphilis repeat-reactive (RR) results lead to the indefinite deferral of CBS donors regardless of supplementary test results. We have previously described a temporal association of RR results with seasonal public health influenza vaccination campaigns that generally start in September and continue through winter. As of December 2020, there has also been an intensive COVID-19 public health vaccination campaign in Canada. Aims: To track temporal associations between RR, unconfirmed syphilis results among CBS blood donors and Canadian influenza and COVID-19 vaccination campaigns. Methods: All donations were tested on the PK 7300 instrument (Beckman Coulter;Brea, CA, USA) with the PK TP system test kit. Confirmatory laboratory testing was undertaken at reference laboratories using the Treponema pallidum particle agglutination (TP-PA) test. Syphilis RR results that did not confirm were obtained for CBS donations between September 2017 to January 2022. Data on donor influenza and COVID-19 vaccination histories, within 3 months of donation, were extracted. The temporal periodicity of unconfirmed syphilis RR results was graphed against vaccination data. Respiratory virus data were acquired from the Public Health Agency of Canada Respiratory Virus Detection Surveillance System. Results: Periodicity of RR, unconfirmed syphilis rates: September 2017-January 2022. Summary/Conclusions: We have previously noted a cyclical temporal trend in the number of RR, unconfirmed syphilis specimens with peaks corresponding to influenza vaccine campaigns or widespread community circulation of respiratory viruses. Although insufficient to establish a causal association, this analysis suggests that incidence of RR, unconfirmed syphilis results in Canadian blood donors may be variably influenced at different times of year by one or more of at least three factors: (1) influenza vaccination campaigns, (2) the COVID-19 vaccination campaign, and (3) circulation of respiratory viruses in the presence or absence of circulating seasonal influenza. Moreover, other mechanisms may affect these trends. For example, syphilis assays such as the PK TP test kit that detect IgM may be prone to false positive results that do not confirm either after influenza vaccine, COVID- 19 vaccination or during a respiratory virus season. (Table Presented).

Special Issue: All subjects about laboratory sciences in emerging diseases. (Special Issue: All subjects about laboratory sciences in emerging diseases.)

This special issue contains 10 papers on the following topics: evaluating association between ABO blood groups and COVID 19;impact of COVID-19 on Libyan laboratory specialists;microscopic agglutination test for diagnosis of leptospirosis by using filter paper-dried serum samples;prevalence of haemoparasites among blood donors in Calabar, Nigeria;assessment of peripheral blood lymphocytosis in adults and determination of thresholds for differential diagnosis between clonal and reactive lymphocytosis;investigation of antibiotic resistance pattern in isolates from urine and blood samples of patients admitted to the Intensive Care Unit of Velayat Hospital in Qazvin, Iran;evaluation of rejection rates and reasons among specimens taken from different hospital units;quality tools to ensure patient safety and reduce the turnaround time of medical laboratories in tertiary care teaching hospitals;prevalence and antibiotic resistance pattern of Gram-positive isolates from burn patients in Velayat Burn Center in Rasht, North of Iran;and infective endocarditis caused by Staphylococcus aureus in a 6-year-old girl with no history of heart and dental problems.

Antibody Response following Exposure to SARS-CoV-2: Is It a Reliable Marker of Immunity?

Introduction: Infection and vaccination with the viral vector vaccine Covishield are both expected to produce immunity in the body against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Production of neutralising antibodies as a result of the humoral immune response plays a key role in defending against this deadly infection. A lack of virus-specific antibodies in the serum does not always imply a lack of immunological memory. The immune response mediated by T cells is also important. Aim: To check for the humoral immune response after exposure to the SARS-CoV-2 virus. Materials and Methods: This cross-sectional observational research was carried out at Central Referral Hospital (CRH), a tertiary care hospital in Gangtok, Sikkim from May-June 2021. A total of 90 participants were divided into three equal groups;unvaccinated with a history of infection with SARS-CoV-2 in the recent past, vaccinated but no infection, and history of vaccination and infection both, respectively. The test was performed with COVISCREEN. It's a double antigen sandwich immunoassay that can detect total antibodies (IgM+IgG+IgA) simultaneously to the SARS-CoV-2 virus. The Statistical Package for the Social Sciences (SPSS), version 16.0 for Windows, was used to analyse the data. Results: Overall, 30 (33.3%) participants showed positive antibody tests out of total 90. Participants with prior infection exhibited more antibody responses irrespective of the vaccination status as compared to vaccinated participants with no prior infection, this difference was statistically insignificant (p=0.165). Conclusion: Both B-cell, as well as T-cell immune responses following infection and vaccination, need to be evaluated to predict long term immunological memory and protective immunity against future infections with SARS-CoV-2.

Risk Factors for Acute Brucellosis in Patients on the Day of Admission at Selected Hospitals of Abbottabad, Pakistan.

Brucellosis is a neglected zoonotic disease of ruminants. It causes severe health problems in humans and significant economic loss. Only a limited number of studies have been conducted in Pakistan to determine the prevalence of human brucellosis and related risk factors. The objectives of the current cross-sectional study were to determine the prevalence of anti-Brucella antibodies in sera collected from symptomatic patients at three hospitals of Abbottabad using a commercial slide agglutination test (SAT) and to determine risk factors for brucellosis for these patients. Five hundred blood samples were collected. A questionnaire was filled in for each patient to obtain information on age, gender, living area, brucellosis associated symptoms, associated risk factors, pregnancy and abortion history. A total of 13.6% (n = 68) patients were found to be SAT positive and in 83.3% (n = 57) of these samples Brucella DNA was detected by genus specific RT-PCR for BCSP-31 gene. Statistical analysis was performed to determine odd ratios, risk ratios, 95% confidence intervals, and p-values. The prevalence of brucellosis by SAT was reported to be higher in women (14.6%, n = 44) than in men (12.1%, n = 24). The age group 25-50 years was found to be at higher risk for brucellosis (14.5%, n = 50) "animal contact" was reported as the main risk factor followed by "consumption of raw animal products." Out of 131 pregnant women and 21 patients had abortion, the seropositivity of Brucellosis was 9.9% and 23.8%, respectively. The present study reports a striking prevalence of brucellosis among patients including pregnant women at three hospitals of Abbottabad. These findings may foster strategies for controlling human brucellosis at household level, raising of awareness about brucellosis in hospital and family doctors, and finally in setting up an eradication program in the dairy industry.

Rapid Quantitative Point-Of-Care Diagnostic Test for Post COVID-19 Vaccination Antibody Monitoring.

Point-of-care (POC) quantification of antibody responses against SARS-CoV-2 spike protein can enable decentralized monitoring of immune responses after infection or vaccination. We evaluated a novel POC microfluidic cartridge-based device (ViroTrack Sero COVID-19 Total Ab) for quantitative detection of total antibodies against SARS-CoV-2 spike trimeric spike protein compared to standard laboratory chemiluminescence (CLIA)-based tests. Antibody responses of 101 individuals were measured on capillary blood, venous whole blood, plasma, and diluted plasma samples directly on the POC. Results were available within 7 min. As the reference, plasma samples were analyzed on DiaSorin LIAISON XL CLIA analyzer using LIAISON SARS-CoV-2 IgM, LIAISON SARS-CoV-2 S1/S2 IgG, and LIAISON SARS-CoV-2 TrimericS IgG assays. The Spearman rank's correlation coefficient between ViroTrack Sero COVID-19 Total Ab and LIAISON SARS-CoV-2 S1/S2 IgG and LIAISON SARS-CoV-2 TrimericS IgG assays was found to be 0.83 and 0.89, respectively. ViroTrack Sero COVID-19 Total Ab showed high correlation between the different matrixes. Agreement for determination of samples of >230 binding antibody units (BAU)/mL on POC and CLIA methods is estimated to be around 90%. ViroTrack Sero Covid Total Ab is a rapid and simple-to-use POC test with high sensitivity and correlation of numerical results expressed in BAU/mL compared to those of a commercial CLIA assay. IMPORTANCE Serological testing is an important diagnostic support tool in the fight against COVID-19. So far, serological testing has been performed on either lateral flow assays, which perform only qualitatively and can be difficult for the individual to read, or standard laboratory assays, which are time- and resource-consuming. The purpose of the study was to evaluate the performance of a new POC microfluidic cartridge-based device based on immunomagnetic agglutination assay that can provide an accurate numerical quantification of the total antibodies within only 7 min from a single drop of capillary blood. We demonstrated a high level of correlation between the POC and the two CLIA laboratory-based immunoassays from Diasorin, thus allowing a potentially wider use of quantitative serology tests in the COVID-19 pandemic.

CRP was found to be an independent discriminator in COVID19 patients

Background: The outbreak of novel Coronavirus Disease 2019 has led to the pandemic. This virus is causing severe acute respiratory syndrome, with increasing morbidity and mortality and yet to find a vaccine for the virus. Several inflamma- tory markers help in early pickup of severely affected patients. One of the inflammatory marker is C reactive protein. Methods: A prospective study was done from Sep 2020 to Nov 2020. We collected 200 samples from inpatients in COVID wards. CRP was done by passive agglutination test, and the positive value was expressed in mg/L. Results: After statistical analysis, Out of 200 COVID positive patients 71 were >60 years of age, 56 were 41-60 years of age, and 22 were in 19-40 years of age group. There were no patients below 19 years of age in our hospital. Positive CRP value was present around 36% in age group of >60 years of age group, 28% in 41-60 age group and 11% in 19-40 years of age group. [Formula presented] Conclusions: In patients with COVID-19, CRP has correlated with the advancing age group, also tended to be a good predictor of adverse out- come

Hemolysis in COVID 19 Positive Patients: 2 Case Reports

Introduction: The presentation of SARS-CoV-2 (COVID 19) isvaried. Although, respiratory system is predominantly affected, AIHAboth warm and cold antibody types have also been reported in somepatients. We worked up 2 such patients who presented to us withCOVID symptoms along with unexplained hemolysis. The 1st patientpresented with mucormycosis and was on Amphotericin B. Bothpatients had history of blood transfusion. The 2nd patient on examination was found to have generalized lymphadenopathy. Peripheralsmear of 1st patient showed morphological features of hemolysis. Theother patient showed agglutination on peripheral smear that resolvedon preheating of sample before smear formation. On further workup,both showed Direct Agglutination Test (DAT) positivity with presence of autoantibodies as well as alloantibodies.Aims &Objectives: To workup and establish the cause of hemolysisin COVID positive patients.Materials &Methods: Routine complete blood count and peripheralsmear studies were performed for these patients along with relevantbiochemical tests. Samples were subjected to DAT and antibodyscreening. Both 3 cell and 11 cell panel testing was done by gel cardmethod (Bio Rad).Result: DAT was positive in both the cases, with IgG positivity in 1stcase, indicative of warm antibodies. 2nd case showed presence ofmixed antibodies with IgG, IgA, C3d, IgM and C3c positivity. Onextended antibody panel testing, 2-3 + reactivity was seen in bothcases in the whole panel with auto control positivity, indicative ofpresence of both auto and alloantibodies.Conclusions: Although immune mediated hemolysis in COVIDpatients is not uncommon, it should be labelled as the cause only afterall other common causes have been thoroughly looked into and ruledout.

ABO blood group system and Covid-19 susceptibility in different ethnic groups of medical students in Karachi

Objective: To determine the frequency of blood group in different ethnicity among medical students of Karachi and their association with the covid 19 susceptibility Methodology: A cross sectional study was conducted among medical students of Liaquat College of medicine and dentistry from 1stJune to 30th November 2020. Data was collected from students which were of different ethnicities. Blood group was determined by mixing the blood with antisera and observing the agglutination by antigen and antibody reaction. Screening for covid 19 was carried out by reverse transcription polymerase chain reaction real-time (RT-PCR) Result In our study, data was collected from 220 medical students, out of which 89(40.5%) were male and 131(59.5%) were female participants. Their age ranges from 17-22 years with mean age of 19.5+ 2.39 years. Among 220 students, group B was the most common group, accounting for 77 (35%). Upon screening the most susceptible blood group for Covid19 virus was Blood group B (61%) Conclusion: Our study concluded that according to ethnicity blood group B was the commonest group in Punjabi and Urdu speaking casts while in Sindhi blood group A and O being the prevalent group. The Rh positive groups found to be more susceptible for covid 19 virus and blood group B+ appears to be in higher association with it.

Column Agglutination Assay Using Polystyrene Microbeads for Rapid Detection of Antibodies against SARS-CoV-2.

Rapid serology platforms are essential in disease pandemics for a variety of applications, including epidemiological surveillance, contact tracing, vaccination monitoring, and primary diagnosis in resource-limited areas. Laboratory-based enzyme-linked immunosorbent assay (ELISA) platforms are inherently multistep processes that require trained personnel and are of relatively limited throughput. As an alternative, agglutination-based systems have been developed; however, they rely on donor red blood cells and are not yet available for high-throughput screening. Column agglutination tests are a mainstay of pretransfusion blood typing and can be performed at a range of scales, ranging from manual through to fully automated testing. Here, we describe a column agglutination test using colored microbeads coated with recombinant SARS-CoV-2 spike protein that agglutinates when incubated with serum samples collected from patients recently infected with SARS-CoV-2. After confirming specific agglutination, we optimized centrifugal force and time to distinguish samples from uninfected vs SARS-CoV-2-infected individuals and then showed concordant results against ELISA for 22 clinical samples, and also a set of serial bleeds from one donor at days 6-10 postinfection. Our study demonstrates the use of a simple, scalable, and rapid diagnostic platform that can be tailored to detect antibodies raised against SARS-CoV-2 and can be easily integrated with established laboratory frameworks worldwide.

COVID-19 Antibody Detection and Assay Performance Using Red Cell Agglutination.

Red cells can be labeled with peptides from the SARS-CoV-2 spike protein (C-19 kodecytes) and used as reagent cells for serologic screening of SARS-CoV-2 antibodies. We evaluated 140 convalescent COVID-19 donors and 275 healthy controls using C19-kodecytes. The analytical performance of the C19-kodecyte assay was compared with a virus neutralizing assay and two commercial chemiluminescent antibody tests (Total assay and IgG assay, Ortho). The C19-kodecyte assay detected SARS-CoV-2 antibodies with a sensitivity of 92.8% and specificity of 96.3%, well within the minimum performance range required by FDA for EUA authorization of serologic tests. The Cohen's kappa coefficient was 0.90 indicating an almost perfect agreement with the Total assay. The Spearman's correlation coefficient was 0.20 with the neutralizing assay (0.49 with IgG, and 0.41 with Total assays). The limited correlation in assay reaction strengths suggested that the assays may be influenced by different antibody specificities. The C19-kodecyte assay is easily scalable and may vastly improve test capacity in any blood typing laboratory using its routine column agglutination platforms. IMPORTANCE We recently developed a red cell based assay to detect SARS-CoV-2 antibodies in human plasma. In the current study, we show the hands-on application of this assay in a group of COVID-19 convalescent plasma donors and healthy individuals. We compared our assay against three published assays, including two that are widely used for patient care in the United States. Our assay compared well with all three assays. Our easily scalable assay can be used for population-wide screening of SARS-CoV-2 antibody status. It can be readily established in any hospital blood bank worldwide using its routine equipment.

Rapid and accurate agglutination-based testing for SARS-CoV-2 antibodies.

We have developed a rapid, accurate, and cost-effective serologic test for SARS-CoV-2 virus, which caused the COVID-19 pandemic, on the basis of antibody-dependent agglutination of antigen-coated latex particles. When validated using plasma samples that are positive or negative for SARS-CoV-2, the agglutination assay detected antibodies against the receptor-binding domain of the spike (S-RBD) or the nucleocapsid protein of SARS-CoV-2 with 100% specificity and ∼98% sensitivity. Furthermore, we found that the strength of the S-RBD antibody response measured by the agglutination assay correlated with the efficiency of the plasma in blocking RBD binding to the angiotensin-converting enzyme 2 in a surrogate neutralization assay, suggesting that the agglutination assay might be used to identify individuals with virus-neutralizing antibodies. Intriguingly, we found that >92% of patients had detectable antibodies on the day of a positive viral RNA test, suggesting that the agglutination antibody test might complement RNA testing for the diagnosis of SARS-CoV-2 infection.

Evaluation of commercially available immuno-magnetic agglutination in comparison to enzyme-linked immunosorbent assays for rapid point-of-care diagnostics of COVID-19.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is caused by Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Fast, accurate, and simple blood-based assays for quantification of anti-SARS-CoV-2 antibodies are urgently needed to identify infected individuals and keep track of the spread of disease. METHODS: The study included 33 plasma samples from 20 individuals with confirmed COVID-19 by real-time reverse-transcriptase polymerase chain reaction and 40 non-COVID-19 plasma samples. Anti-SARS-CoV-2 immunoglobulin M (IgM)/immunoglobulin A (IgA) or immunoglobulin G (IgG) antibodies were detected by a microfluidic quantitative immunomagnetic assay (IMA) (ViroTrack Sero COVID IgM + IgA/IgG Ab, Blusense Diagnostics) and compared to an enzyme-linked immunosorbent assay (ELISA) (EuroImmun Medizinische Labordiagnostika). RESULTS: Of the 33 plasma samples from the COVID-19 patients, 28 were positive for IgA/IgM or IgG by IMA and 29 samples were positive by ELISA. Sensitivity for only one sample per patient was 68% for IgA + IgM and 75% IgG by IMA and 80% by ELISA. For samples collected 14 days after symptom onset, the sensitivity of both IMA and ELISA was around 91%. The specificity of the IMA reached 100% compared to 95% for ELISA IgA and 97.5% for ELISA IgG. CONCLUSION: IMA for COVID-19 is a rapid simple-to-use point-of-care test with sensitivity and specificity similar to a commercial ELISA.

Sensitive and Specific Detection of SARS-CoV-2 Antibodies Using a High-Throughput, Fully Automated Liquid-Handling Robotic System.

As of July 22, 2020, more than 14.7 million infections of SARS-CoV-2, the virus responsible for Coronavirus Disease 2019 (COVID-19), have been confirmed globally. Serological assays are essential for community screening, assessing infection prevalence, aiding identification of infected patients, and enacting appropriate treatment and quarantine protocols in the battle against this rapidly expanding pandemic. Antibody detection by agglutination-PCR (ADAP) is a pure solution phase immunoassay that generates a PCR amplifiable signal when patient antibodies agglutinate DNA-barcoded antigen probes into a dense immune complex. Here, we present an ultrasensitive and high-throughput automated liquid biopsy assay based on the Hamilton Microlab ADAP STAR automated liquid-handling platform, which was developed and validated for the qualitative detection of total antibodies against spike protein 1 (S1) of SARS-CoV-2 that uses as little as 4 µL of serum. To assess the clinical performance of the ADAP assay, 57 PCR-confirmed COVID-19 patients and 223 control patients were tested. The assay showed a sensitivity of 98% (56/57) and a specificity of 99.55% (222/223). Notably, the SARS-CoV-2-negative control patients included individuals with other common coronaviral infections, such as CoV-NL63 and CoV-HKU, which did not cross-react. In addition to high performance, the hands-free automated workstation enabled high-throughput sample processing to reduce screening workload while helping to minimize analyst contact with biohazardous samples. Therefore, the ADAP STAR liquid-handling workstation can be used as a valuable tool to address the COVID-19 global pandemic.

Rapid Gel Card Agglutination Assays for Serological Analysis Following SARS-CoV-2 Infection in Humans.

High-throughput and rapid serology assays to detect the antibody response specific to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) in human blood samples are urgently required to improve our understanding of the effects of COVID-19 across the world. Short-term applications include rapid case identification and contact tracing to limit viral spread, while population screening to determine the extent of viral infection across communities is a longer-term need. Assays developed to address these needs should match the ASSURED criteria. We have identified agglutination tests based on the commonly employed blood typing methods as a viable option. These blood typing tests are employed in hospitals worldwide, are high-throughput, fast (10-30 min), and automated in most cases. Herein, we describe the application of agglutination assays to SARS-CoV-2 serology testing by combining column agglutination testing with peptide-antibody bioconjugates, which facilitate red cell cross-linking only in the presence of plasma containing antibodies against SARS-CoV-2. This simple, rapid, and easily scalable approach has immediate application in SARS-CoV-2 serological testing and is a useful platform for assay development beyond the COVID-19 pandemic.