scholarly journals Clinical Evaluation of an Immunochromatographic-Based IgM/IgG Antibody Assay (GenBody™ COVI040) for Detection of Antibody Seroconversion in Patients with SARS-CoV-2 Infection

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 537
Author(s):  
Doyeong Kim ◽  
Jihoo Lee ◽  
Jyotiranjan Bal ◽  
Chom-Kyu Chong ◽  
Jong Ho Lee ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Negative Control ◽  
Immunoglobulin M ◽  
Antibody Assay ◽  
Igg Antibody ◽  
South Korean ◽  
Korean Ministry ◽  
In Vitro Diagnostic ◽  
Polymerase Chain

There is a need for accurate diagnostic tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease (COVID-19). This study aimed to evaluate the diagnostic accuracy of an immunochromatography-based immunoglobulin G (IgG)/immunoglobulin M (IgM) antibody assay (GenBody™ COVI040) for detecting SARS-CoV-2 antibody seroconversion in COVID-19 patients. A total of 130 samples, serially collected from patients with confirmed COVID-19, and 100 negative control samples were tested for anti-SARS-CoV-2 IgM and IgG using the GenBody™ COVI040 assay following the South Korean Ministry of Food and Drug Safety guidelines on the review and approval of in vitro diagnostic devices for COVID-19. Reverse-transcription polymerase chain reaction results were used as the comparator. The overall sensitivity of the GenBody™ COVI040 assay was 97.69% (95% confidence interval (CI): 93.40–99.52%). The sensitivity of the assay increased with time post symptom onset (PSO) (sensitivity ≤6 days PSO: 78.57%, 95% CI: 49.20–95.34%; sensitivity 7–13 days PSO: 100%, 95% CI: 87.23–100%; and sensitivity ≥14 days PSO: 100%, 95% CI: 95.94–100%). The specificity of the assay was 100% (95% CI: 96.38–100%). The GenBody™ COVI040 assay showed high sensitivity and specificity, making it a promising diagnostic test to monitor COVID-19.

scholarly journals Seroprevalence of Anti-SARS-CoV-2 IgG and IgM among Adults over 65 Years Old in the South of Italy

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 483
Author(s):  
Immacolata Polvere ◽  
Alfredina Parrella ◽  
Giovanna Casamassa ◽  
Silvia D’Andrea ◽  
Annamaria Tizzano ◽  
...  
Keyword(s):  
Antibody Response ◽  
Immunoglobulin M ◽  
Molecular Testing ◽  
Elisa Assay ◽  
The South ◽  
Serum Samples ◽  
Serological Screening ◽  
Rna Detection ◽  
In Vitro Diagnostic

SARS-CoV-2 is a zoonotic betacoronavirus associated with worldwide transmission of COVID-19 disease. By the beginning of March, WHO reported about 113,820,000 confirmed cases including more than 2,527,000 deaths all over the world. However, the true extent of virus circulation or its real infection/fatality ratio is not well-estimated due to the huge portion of asymptomatic infections. In this observational study, we have estimated the prevalence of specific immunoglobulin M and G directed towards SARS-CoV-2 antigen in a cohort of 1383 adult volunteers aged over 65 years old, living in the district of Benevento, in the South of Italy. Serological screening was carried out on capillary blood in September 2020, seven months after pandemic outbreak in Italy, to evaluate virus circulation and antibody response among elderly adults, in which severe symptoms due to viral infection are more common. The overall seroprevalence of anti-SARS-CoV-2 antibodies was 4.70% (CI 3.70%–5.95%) with no statistically significant differences between sexes. Among these, 69.69% (CI 55.61%–77.80%) tested positive to IgM, 23.08% (CI 14.51%–34.64%) to IgG and 9.23% (CI 4.30%–18.71%) was positive for both. All patients that were positive to IgM underwent molecular testing through RT-qPCR on oral-rhino pharyngeal swabs and only one specimen was positive for SARS-CoV-2 RNA detection. Instead, the presence of IgG from screened volunteers was confirmed by re-testing serum samples using both an ELISA assay validated for in vitro diagnostic use (IVD) and a recently published synthetic peptide-based ELISA assay. In conclusion, our report suggests that (1) early restrictions were successful in limiting COVID-19 diffusion in the district of Benevento; (2) rapid serological analysis is an ideal testing for both determining real seroprevalence and massive screening, whereas detection of viral RNA remains a gold standard for identification of infected patients; (3) even among people without COVID-19 related symptoms, the antibody response against SARS-CoV-2 antigens has individual features.

scholarly journals Sensitivity of polymerase chain reaction for detection of known aliquots of Trypanosoma cruzi in the blood of mice: an in vitro study

2002 ◽  
Vol 35 (5) ◽  
pp. 487-490 ◽  
Author(s):  
Rozália F. Campos ◽  
Juracy B. Magalhães ◽  
Eliana A.G. Reis ◽  
Mitermayer G. Reis ◽  
Sonia G. Andrade
Keyword(s):  
Polymerase Chain Reaction ◽  
Trypanosoma Cruzi ◽  
In Vitro Study ◽  
High Sensitivity ◽  
Positive Control ◽  
Chain Reaction ◽  
Negative Results ◽  
Polymerase Chain ◽  
Positive Controls

To evaluate the sensitivity of polymerase chain reaction (PCR) to reveal known number of trypomastigote in the blood of mice, three separate experiments were done. First: To eight samples of 500mul of normal mice blood, one aliquot of 1, 2, 3, 4, 5, 10, and 50 trypomastigotes respectively, were added. Second and third: 10 aliquots with 1 and 10 with 2 trypomastigotes were added to samples of 500mul of normal mice blood. Positive control: 500mul of blood containing 100,000 trypomastigotes. For kDNA minicircles amplification by PCR the primers:S35 and S36 were used. PCR revealed products of 330 b.p in the positive controls. When only one sample with the aliquots of 1 or 2 trypomastigotes was examined, results were negative; results were positive with aliquots of 3 to 50 trypomastigotes. In the 2nd and 3rd experiments, 9/10 aliquots with one parasite and 9/10 with 2 trypomastigotes were positive revealing a high sensitivity of this reaction. In conclusion, the presence of one single parasite in 500mul of blood, is enough for a positive PCR. This method could be used as a complement to the various parasitological cure tests in treated mice, when low volumes of blood are individually examined.

scholarly journals Inhibition of cell growth by monoclonal anti-transferrin receptor antibodies.

1985 ◽  
Vol 5 (8) ◽  
pp. 1814-1821 ◽  
Author(s):  
J F Lesley ◽  
R J Schulte
Keyword(s):  
Cell Growth ◽  
Cell Surface ◽  
Transferrin Receptor ◽  
Immunoglobulin M ◽  
Cross Linking ◽  
Igg Antibody ◽  
Igm Antibodies ◽  
Igm Antibody ◽  
Mutant Cells

Five anti-murine transferrin receptor monoclonal antibodies have been characterized with respect to immunoglobulin class, effects on binding of transferrin, and effects on AKR1 lymphoma cell growth in vitro. The immunoglobulin M (IgM) antibodies, but not the IgG antibodies, prevent cell growth. We suggest that the profound effects of the IgM antibodies on cell growth are probably due to extensive cross-linking of cell surface receptors. In support of this, we are able to mimic the growth-inhibiting effects of the IgM antibodies by adding antiimmunoglobulin to an IgG antibody. By flow microfluorimetry, we show that an IgG antibody by itself induces up to a 10-fold downward regulation in the cell surface transferrin receptor, which is accompanied by accelerated receptor degradation. A similar downward regulation is seen in mutant cells resistant to growth inhibition by an IgM antibody, when grown in the selecting antibody. Wild-type cells grown in the presence of IgM antibody do not show receptor downward regulation. Inhibitory effects of antibody plus antiimmuoglobulin on mutant cells are also consistent with extensive cross-linking causing inhibition of growth.

scholarly journals Screen-Printed Electrodes (SPE) for In Vitro Diagnostic Purpose

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 517 ◽  
Author(s):  
Nicolae-Bogdan Mincu ◽  
Veronica Lazar ◽  
Dana Stan ◽  
Carmen Marinela Mihailescu ◽  
Rodica Iosub ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Accurate Diagnosis ◽  
Diagnostic Purpose ◽  
Pathogenic Microorganisms ◽  
Screen Printed Electrodes ◽  
High Incidence ◽  
In Vitro Diagnostic ◽  
Sensitivity And Selectivity ◽  
Screen Printed

Due to rapidly spreading infectious diseases and the high incidence of other diseases such as cancer or metabolic syndrome, there is a continuous need for the development of rapid and accurate diagnosis methods. Screen-printed electrodes-based biosensors have been reported to offer reliable results, with high sensitivity and selectivity and, in some cases, low detection limits. There are a series of materials (carbon, gold, platinum, etc.) used for the manufacturing of working electrodes. Each version comes with advantages, as well as challenges for their functionalization. Thus, the aim is to review the most promising biosensors developed using screen-printed electrodes for the detection/quantification of proteins, biomarkers, or pathogenic microorganisms.

scholarly journals Development of an NT-ProBNP Assay Reagent Based on High Specific Activity Alkaline Phosphatase CmAP and an Improved Coupling Method

2020 ◽  
Vol 10 (23) ◽  
pp. 8682
Author(s):  
Hai-Chao Li ◽  
Xin He ◽  
Shan-Peng Qiao ◽  
Zhen-Ni Liu ◽  
Yu-Zhou Gao
Keyword(s):  
Alkaline Phosphatase ◽  
Magnetic Beads ◽  
Specific Activity ◽  
High Specific Activity ◽  
High Sensitivity ◽  
Coupling Method ◽  
Purification Method ◽  
In Vitro Diagnostic ◽  
Diagnostic Reagent

(1) Background: Chemiluminescent enzyme immunoassay (CLEIA) is an efficient analytical method. Alkaline phosphatase (ALP) with high specific activity is the basis for CLEIA to achieve high sensitivity. In this study, a high specific activity Cobetia marina ALP (CmAP) and an improved coupling method were used to develop an N-terminal pro-B-type natriuretic peptide (NT-proBNP) diagnostic reagent. (2) Methods: The purification method of CmAP was improved and the related enzyme activities were assessed. The enzyme and magnetic beads were coupled only to the Fc region of the detection antibody and the capture antibody, respectively, by using a specially improved method. The NT-proBNP in human serum was assessed. (3) Results: The specific activity of the purified CmAP was found to be 13,133 U/mg. No loss in the enzyme activity was observed after its storage at room temperature for 4 months. The sensitivity of the in vitro diagnostic reagents was found to be 0.58 ng/L. (4) Conclusions: CmAP can be applied as a substitute for the commercial ALP. Analytical parameters indicated that the chemiluminescence diagnostic reagent for NT-proBNP is adequately sensitive and reliable for detecting the serum NT-proBNP, which suggests that both the enzyme and coupling method are suitable for the CLEIA.

scholarly journals RT-qPCR-based tests for SARS-CoV-2 detection in pooled saliva samples for massive population screening to monitor epidemics.

2021 ◽  
Author(s):  
Michal Rozanski ◽  
Aurelia Walczak-Drzewiecka ◽  
Jolanta Witaszewska ◽  
Ewelina Wojcik ◽  
Arkadiusz Guzinski ◽  
...  
Keyword(s):  
Screening Test ◽  
False Negative ◽  
Clinical Samples ◽  
Highly Sensitive ◽  
In Vitro Diagnostic ◽  
Polymerase Chain ◽  
Asymptomatic Individuals ◽  
Pooled Samples ◽  
Rna Concentration

Swab, quantitative, reverse transcription polymerase chain reaction (RT-qPCR) tests remain the gold standard of diagnostics of SARS-CoV-2 infections. However, these tests are costly and time-consuming, and swabbing limits their throughput. We developed a 3-gene, seminested RT qPCR test with SYBR green-based detection, optimized for testing pooled saliva samples for high-throughput diagnostics of epidemic-affected populations. The proposed two-tier approach depends on decentralized self-collection of saliva samples, pooling, 1st-tier testing with the mentioned highly sensitive screening test and subsequent 2nd-tier testing of individual samples from positive pools with the in vitro diagnostic (IVD) test. The screening test was able to detect 5 copies of the viral genome in 10 μl of isolated RNA with 50% probability and 18.8 copies with 95% probability and reached Ct values that were highly linearly RNA concentration-dependent. In the side-by-side comparison (testing artificial pooled samples), the screening test attained slightly better results than the commercially available IVD-certified RT-qPCR diagnostic test (100% specificity and 89.8% sensitivity vs. 100% and 73.5%, respectively). Testing of 1475 individual clinical samples pooled in 374 pools of 4 revealed 0.8% false positive pools and no false negative pools. In weekly prophylactic testing of 113 people within 6 months, a two-tier testing approach enabled the detection of 18 infected individuals, including several asymptomatic individuals, with a fraction of the costs of individual RT-PCR testing.

scholarly journals In Vitro Diagnostic Assays for COVID-19: Recent Advances and Emerging Trends

Diagnostics ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 202 ◽  
Author(s):  
Sandeep Kumar Vashist
Keyword(s):  
Point Of Care ◽  
The United States ◽  
Immunoglobulin M ◽  
Ongoing Research ◽  
Molecular Tests ◽  
Emerging Trends ◽  
Wide Range ◽  
United States Food ◽  
In Vitro Diagnostic

There have been tremendous advances in in vitro diagnostic (IVD) assays for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The main IVD assays used for COVID-19 employ real-time reverse transcriptase polymerase chain reaction (RT-PCR) that takes a few hours. But the assay duration has been shortened to 45 min by Cepheid. Of interest is the point-of-care (POC) molecular assay by Abbott that decreased the assay duration to just 5 min. Most molecular tests have been approved by the United States Food and Drug Administration (FDA) under emergency use authorization (EUA) and are Conformité Européenne (CE) marked. A wide range of serology immunoassays (IAs) have also been developed that complement the molecular assays for the diagnosis of COVID-19. The most prominent IAs are automated chemiluminescent IA (CLIA), manual ELISA, and rapid lateral flow IA (LFIA), which detect the immunoglobulin M (IgM) and immunoglobulin G (IgG) produced in persons in response to SARS-CoV-2 infection. The ongoing research efforts and advances in complementary technologies will pave the way to new POC IVD assays in the coming months. However, the performance of IVD assays needs to be critically evaluated before they are employed for the clinical diagnosis of COVID-19.

scholarly journals Validasi Metode Analisis Cemaran DNA Babi pada Bakso Sapi Menggunakan Primer Mitokondria D-Loop22 dengan Metode Polymerase Chain Reaction (PCR)

2019 ◽  
Vol 5 (1) ◽  
pp. 65-72
Author(s):  
Sri Wahyuni ◽  
Siti Maryam ◽  
Aminah Aminah
Keyword(s):  
Polymerase Chain Reaction ◽  
Pcr Amplification ◽  
High Sensitivity ◽  
Negative Control ◽  
Chain Reaction ◽  
Food Authentication ◽  
Fresh Tissue ◽  
Dna Contamination ◽  
Polymerase Chain ◽  
Processed Products

The frequency of non-halal ingredient mixing, such as porkin on the food processed products of meatballs, has become an issue to the public, especially for moslems. Therefore, a reliable and valid method with high sensitivity is needed to specifically detect the pig contamination. This research aims to obtain a valid and reliable method by proposing polymerase chain reaction (PCR)  using mitochondrial D-Loop22 primer as a method in handing halal food authentication. The sample consisted of beef as a negative control, pork and pork meatballs as a positivecontrol, and five samples of meat balls found in Makassar for halal inspection.The method validation assay was conducted by testing the primary specificity on the fresh tissue (beef and pork) and testing the sensitivity by making a series of pig DNA dilution (1:10;  1:102;   1:103;   1:104)   and the variations of contaminated pig:cow (%b/b) : 0.05% , 0.1%, 1%, and 5%. The result of PCR amplification on agarose gel electrophoresis of 0.8% showed that method was able to detect the pig DNA contamination specifically in pigs and not amplify other DNA, and could still be detected up to pig contamination specifically in pigs and not amplify the other DNAs and could still be detected up to pig contamination of 0.05% and on DNA dilution of 1:103. Meanwhile, on the five samples analyzed, there were  not found pig DNA contamination characterized by no formed amplification bands.

Inhibition of cell growth by monoclonal anti-transferrin receptor antibodies

1985 ◽  
Vol 5 (8) ◽  
pp. 1814-1821
Author(s):  
J F Lesley ◽  
R J Schulte
Keyword(s):  
Cell Growth ◽  
Cell Surface ◽  
Transferrin Receptor ◽  
Immunoglobulin M ◽  
Cross Linking ◽  
Igg Antibody ◽  
Igm Antibodies ◽  
Igm Antibody ◽  
Mutant Cells

Five anti-murine transferrin receptor monoclonal antibodies have been characterized with respect to immunoglobulin class, effects on binding of transferrin, and effects on AKR1 lymphoma cell growth in vitro. The immunoglobulin M (IgM) antibodies, but not the IgG antibodies, prevent cell growth. We suggest that the profound effects of the IgM antibodies on cell growth are probably due to extensive cross-linking of cell surface receptors. In support of this, we are able to mimic the growth-inhibiting effects of the IgM antibodies by adding antiimmunoglobulin to an IgG antibody. By flow microfluorimetry, we show that an IgG antibody by itself induces up to a 10-fold downward regulation in the cell surface transferrin receptor, which is accompanied by accelerated receptor degradation. A similar downward regulation is seen in mutant cells resistant to growth inhibition by an IgM antibody, when grown in the selecting antibody. Wild-type cells grown in the presence of IgM antibody do not show receptor downward regulation. Inhibitory effects of antibody plus antiimmuoglobulin on mutant cells are also consistent with extensive cross-linking causing inhibition of growth.

Characterization of the Original Christmas Disease Mutation (Cysteine 206 → Serine): From Clinical Recognition to Molecular Pathogenesis

1992 ◽  
Vol 67 (01) ◽  
pp. 063-065 ◽  
Author(s):  
Sherryl A M Taylor ◽  
Jacalyn Duffin ◽  
Cherie Cameron ◽  
Jerome Teitel ◽  
Bernadette Garvey ◽  
...  
Keyword(s):  
Nucleotide Substitution ◽  
Novel Mutation ◽  
Factor Ix ◽  
Causative Mutation ◽  
Coding Region ◽  
Body Of Knowledge ◽  
Polymerase Chain ◽  
Splice Junctions

SummaryChristmas disease was first reported as a distinct clinical entity in two manuscripts published in 1952 (1, 2). The eponym associated with this disorder, is the surname of the first patient examined in detail and reported by Biggs and colleagues in a paper describing the clinical and laboratory features of seven affected individuals (3). This patient has severe factor IX coagulant deficiency (less than 0.01 units/ml) and no detectable circulating factor IX antigen (less than 0.01 units/ml). Coding sequence and splice junctions of the factor IX gene from this patient have been amplified in vitro through the polymerase chain reaction (PCR). One nucleotide substitution was identified at nucleotide 30,070 where a guanine was replaced by a cytosine. This mutation alters the amino acid encoded at position 206 in the factor IX protein from cysteine to serine. The non conservative nature of this substitution, the absence of this change in more than 200 previously sequenced factor IX genes and the fact that the remainder of the coding region of this gene was normal, all provide strong circumstantial evidence in favour of this change being the causative mutation in this patient. The molecular characterization of this novel mutation in the index case of Christmas disease, contributes to the rapidly expanding body of knowledge pertaining to Christmas disease pathogenesis.

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