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HasilTes Antibodi Kuantitatif COVID-19. Tingkat akurasi suatu tes antibodi dipengaruhi oleh seberapa sensitif dan spesifik alat dan metode yang digunakan untuk mendeteksi virus SARS-CoV-2. Berdasarkan uji penelitian yang ada, tes antibodi kuantitatif COVID-19 memiliki tingkat akurasi 99% hingga 100%. . 2022 Jan;941388-392. doi Epub 2021 Aug 31. Affiliations PMID 34415572 PMCID PMC8426838 DOI Free PMC article Correlation between a quantitative anti-SARS-CoV-2 IgG ELISA and neutralization activity Ramona Dolscheid-Pommerich et al. J Med Virol. 2022 Jan. Free PMC article Abstract In the current COVID-19 pandemic, a better understanding of the relationship between merely binding and functionally neutralizing antibodies is necessary to characterize protective antiviral immunity following infection or vaccination. This study analyzes the level of correlation between the novel quantitative EUROIMMUN Anti-SARS-CoV-2 QuantiVac ELISA IgG and a microneutralization assay. A panel of 123 plasma samples from a COVID-19 outbreak study population, preselected by semiquantitative anti-SARS-CoV-2 IgG testing, was used to assess the relationship between the novel quantitative ELISA IgG and a microneutralization assay. Binding IgG targeting the S1 antigen was detected in 106 samples using the QuantiVac ELISA, while 89 samples showed neutralizing antibody activity. Spearman's correlation analysis demonstrated a strong positive relationship between anti-S1 IgG levels and neutralizing antibody titers rs = p < High and low anti-S1 IgG levels were associated with a positive predictive value of for high-titer neutralizing antibodies and a negative predictive value of for low-titer neutralizing antibodies, respectively. These results substantiate the implementation of the QuantiVac ELISA to assess protective immunity following infection or vaccination. Keywords COVID-19; ELISA; SARS-CoV-2; microneutralization. © 2021 The Authors. Journal of Medical Virology Published by Wiley Periodicals LLC. Conflict of interest statement Sandra Saschenbrecker and Katja Steinhagen are employed by EUROIMMUN Medizinische Labordiagnostika AG, a manufacturer of diagnostic reagents and co‐owner of a patent application pertaining to the detection of antibodies to the SARS‐CoV‐2 S1 antigen. Katja Steinhagen is designated as an inventor. The other authors declare that there are no conflict of interests. Figures Figure 1 Correlation between quantitative ELISA and microneutralization assay. Binding anti‐SARS‐CoV‐2 S1 IgG was determined quantitatively using the QuantiVac ELISA and titers of neutralizing antibodies were determined using the CPE reduction NT assay n = 123. Neutralization titers correspond to reciprocal plasma dilutions protecting 50% of the wells at incubation with 100 TCID50 of SARS‐CoV‐2. Samples with a cytopathic effect CPE equal or similar to the negative control are depicted on the y‐axis. Dotted and dashed lines indicate borderline and positivity cut‐offs, respectively. r s, Spearman rank‐order correlation coefficient Similar articles Inference of SARS-CoV-2 spike-binding neutralizing antibody titers in sera from hospitalized COVID-19 patients by using commercial enzyme and chemiluminescent immunoassays. Valdivia A, Torres I, Latorre V, Francés-Gómez C, Albert E, Gozalbo-Rovira R, Alcaraz MJ, Buesa J, Rodríguez-Díaz J, Geller R, Navarro D. Valdivia A, et al. Eur J Clin Microbiol Infect Dis. 2021 Mar;403485-494. doi Epub 2021 Jan 6. Eur J Clin Microbiol Infect Dis. 2021. PMID 33404891 Free PMC article. SARS-CoV-2 Serologic Assays in Control and Unknown Populations Demonstrate the Necessity of Virus Neutralization Testing. Rathe JA, Hemann EA, Eggenberger J, Li Z, Knoll ML, Stokes C, Hsiang TY, Netland J, Takehara KK, Pepper M, Gale M Jr. Rathe JA, et al. J Infect Dis. 2021 Apr 8;22371120-1131. doi J Infect Dis. 2021. PMID 33367830 Free PMC article. A highly specific and sensitive serological assay detects SARS-CoV-2 antibody levels in COVID-19 patients that correlate with neutralization. Peterhoff D, Glück V, Vogel M, Schuster P, Schütz A, Neubert P, Albert V, Frisch S, Kiessling M, Pervan P, Werner M, Ritter N, Babl L, Deichner M, Hanses F, Lubnow M, Müller T, Lunz D, Hitzenbichler F, Audebert F, Hähnel V, Offner R, Müller M, Schmid S, Burkhardt R, Glück T, Koller M, Niller HH, Graf B, Salzberger B, Wenzel JJ, Jantsch J, Gessner A, Schmidt B, Wagner R. Peterhoff D, et al. Infection. 2021 Feb;49175-82. doi Epub 2020 Aug 21. Infection. 2021. PMID 32827125 Free PMC article. Quantitative SARS-CoV-2 Serology in Children With Multisystem Inflammatory Syndrome MIS-C. Rostad CA, Chahroudi A, Mantus G, Lapp SA, Teherani M, Macoy L, Tarquinio KM, Basu RK, Kao C, Linam WM, Zimmerman MG, Shi PY, Menachery VD, Oster ME, Edupuganti S, Anderson EJ, Suthar MS, Wrammert J, Jaggi P. Rostad CA, et al. Pediatrics. 2020 Dec;1466e2020018242. doi Epub 2020 Sep 2. Pediatrics. 2020. PMID 32879033 Recent Developments in SARS-CoV-2 Neutralizing Antibody Detection Methods. Banga Ndzouboukou JL, Zhang YD, Fan XL. Banga Ndzouboukou JL, et al. Curr Med Sci. 2021 Dec;4161052-1064. doi Epub 2021 Dec 21. Curr Med Sci. 2021. PMID 34935114 Free PMC article. Review. Cited by Impact of Health Workers' Choice of COVID-19 Vaccine Booster on Immunization Levels in Istanbul, Turkey. Ören MM, Canbaz S, Meşe S, Ağaçfidan A, Demir ÖS, Karaca E, Doğruyol AR, Otçu GH, Tükek T, Özgülnar N. Ören MM, et al. Vaccines Basel. 2023 May 3;115935. doi Vaccines Basel. 2023. PMID 37243039 Free PMC article. Development and validity assessment of ELISA test with recombinant chimeric protein of SARS-CoV-2. Fernandez Z, de Arruda Rodrigues R, Torres JM, Marcon GEB, de Castro Ferreira E, de Souza VF, Sarti EFB, Bertolli GF, Araujo D, Demarchi LHF, Lichs G, Zardin MU, Gonçalves CCM, Cuenca V, Favacho A, Guilhermino J, Dos Santos LR, de Araujo FR, Silva MR. Fernandez Z, et al. J Immunol Methods. 2023 May 11;519113489. doi Online ahead of print. J Immunol Methods. 2023. PMID 37179011 Free PMC article. Dynamics of Antibody Responses after Asymptomatic and Mild to Moderate SARS-CoV-2 Infections Real-World Data in a Resource-Limited Country. Sayabovorn N, Phisalprapa P, Srivanichakorn W, Chaisathaphol T, Washirasaksiri C, Sitasuwan T, Tinmanee R, Kositamongkol C, Nimitpunya P, Mepramoon E, Ariyakunaphan P, Woradetsittichai D, Chayakulkeeree M, Phoompoung P, Mayurasakorn K, Sookrung N, Tungtrongchitr A, Wanitphakdeedecha R, Muangman S, Senawong S, Tangjittipokin W, Sanpawitayakul G, Nopmaneejumruslers C, Vamvanij V, Auesomwang C. Sayabovorn N, et al. Trop Med Infect Dis. 2023 Mar 23;84185. doi Trop Med Infect Dis. 2023. PMID 37104311 Free PMC article. Convalescent Plasma Treatment of Patients Previously Treated with B-Cell-Depleting Monoclonal Antibodies Suffering COVID-19 Is Associated with Reduced Re-Admission Rates. Ioannou P, Katsigiannis A, Papakitsou I, Kopidakis I, Makraki E, Milonas D, Filippatos TD, Sourvinos G, Papadogiannaki M, Lydaki E, Chamilos G, Kofteridis DP. Ioannou P, et al. Viruses. 2023 Mar 15;153756. doi Viruses. 2023. PMID 36992465 Free PMC article. Characterisation of the Antibody Response in Sinopharm BBIBP-CorV Recipients and COVID-19 Convalescent Sera from the Republic of Moldova. Ulinici M, Suljič A, Poggianella M, Milan Bonotto R, Resman Rus K, Paraschiv A, Bonetti AM, Todiras M, Corlateanu A, Groppa S, Ceban E, Petrovec M, Marcello A. Ulinici M, et al. Vaccines Basel. 2023 Mar 13;113637. doi Vaccines Basel. 2023. PMID 36992221 Free PMC article. References Krammer F, Simon F. Serology assays to manage COVID‐19. Science. 2020;3681060‐1061. - PubMed Lee CY, Lin RTP, Renia L, Ng LFP. Serological approaches for COVID‐19 Epidemiologic perspective on surveillance and control. Front Immunol. 2020;11879. - PMC - PubMed Theel ES, Slev P, Wheeler S, Couturier MR, Wong SJ, Kadkhoda K. The role of antibody testing for SARS‐CoV‐2 is there one? J Clin Microbiol. 2020;5858. - PMC - PubMed Zost SJ, Gilchuk P, Case JB, et al. Potently neutralizing and protective human antibodies against SARS‐CoV‐2. Nature. 2020;584443‐449. - PMC - PubMed Rogers TF, Zhao F, Huang D, et al. Isolation of potent SARS‐CoV‐2 neutralizing antibodies and protection from disease in a small animal model. Science. 2020;369956‐963. - PMC - PubMed Publication types MeSH terms Substances LinkOut - more resources Full Text Sources Europe PubMed Central Ovid Technologies, Inc. PubMed Central Wiley Medical Genetic Alliance Miscellaneous NCI CPTAC Assay Portal

Tesantibodi kuantitatif untuk covid-19 ini dilakukan agar dapat mengetahui jumlah antibodi yang spesifik yang ada didalam tubuh. Antibodi tersebut dapat dikatakan dengan SARS-COV-2, kemudian tes ini juga dapat menunjukan hasil dari respon kekebalan tubuh seseorang terhadap virus sars-cov-2 ini. Tes Serologi Covid-19

Loading metrics Open Access Peer-reviewed Research Article Michael Tu, Jordan Cheng, Fang Wei, Feng Li, David Chia, Omai Garner, Sukantha Chandrasekaran, Richard Bender, Charles M. Strom , David T. W. Wong Development and validation of a quantitative, non-invasive, highly sensitive and specific, electrochemical assay for anti-SARS-CoV-2 IgG antibodies in saliva Samantha H. Chiang, Michael Tu, Jordan Cheng, Fang Wei, Feng Li, David Chia, Omai Garner, Sukantha Chandrasekaran, Richard Bender, Charles M. Strom x Published July 1, 2021 Figures AbstractAmperial™ is a novel assay platform that uses immobilized antigen in a conducting polymer gel followed by detection via electrochemical measurement of oxidation-reduction reaction between H2O2/Tetrametylbenzidine and peroxidase enzyme in a completed assay complex. A highly specific and sensitive assay was developed to quantify levels of IgG antibodies to SARS-CoV-2 in saliva. After establishing linearity and limit of detection we established a reference range of 5 standard deviations above the mean. There were no false positives in 667 consecutive saliva samples obtained prior to 2019. Saliva was obtained from 34 patients who had recovered from documented COVID-19 or had documented positive serologies. All of the patients with symptoms severe enough to seek medical attention had positive antibody tests and 88% overall had positive results. We obtained blinded paired saliva and plasma samples from 14 individuals. The plasma was analyzed using an EUA-FDA cleared ELISA kit and the saliva was analyzed by our Amperial™ assay. All 5 samples with negative plasma titers were negative in saliva testing. Eight of the 9 positive plasma samples were positive in saliva and 1 had borderline results. A CLIA validation was performed as a laboratory developed test in a high complexity laboratory. A quantitative non-invasive saliva based SARS-CoV-2 antibody test was developed and validated with sufficient specificity to be useful for population-based monitoring and monitoring of individuals following vaccination. Citation Chiang SH, Tu M, Cheng J, Wei F, Li F, Chia D, et al. 2021 Development and validation of a quantitative, non-invasive, highly sensitive and specific, electrochemical assay for anti-SARS-CoV-2 IgG antibodies in saliva. PLoS ONE 167 e0251342. Chandrabose Selvaraj, Alagappa University, INDIAReceived January 14, 2021; Accepted April 25, 2021; Published July 1, 2021Copyright © 2021 Chiang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are Availability Data is available on figshare DW is supported by U54HL119893, UCLA Keck Foundation Research Award Program. SC is supported by F30DE027615. This study was partially funded by Liquid Diagnostics, LLC LD. The funder provided reimbursement to MT as a paid consultant. This author contributed to this study by performing some experiments and in manuscript preparation. He did not contribute to the decision to publish, data collection or interests CS in an unpaid CEO of LD. CS, MT, RB, and DW are equity holders in LD. LD is the exclusive license holder for the Amperial™ technology from the University of California and hopes to commercialize products based on this technology. This does not alter our adherence to PLOS ONE policies on sharing data an materials. IntroductionA novel corona virus, severe acute respiratory syndrome coronavirus 2 SARS-CoV-2, has caused a global pandemic causing major disruptions world-wide [1]. Multiple high-throughput PCR based tests have been developed that are reasonably sensitive and specific, however the same cannot be said for antibody testing, prompting The Center for Disease Control CDC to issue guidelines entitled “Interim Guidelines for COVID-19 Antibody Testing” [2]. This publication describes the variability of in-home antibody tests and the lack of specificity required to make home-based antibody testing a valuable tool for epidemiologic surveillance. Having a reliable self-collection antibody test may be of enormous help in epidemiologic studies of background immunity, testing symptomatic individuals without RNA based testing during their acute illness, and screening health care providers and first responders to establish prior COVID-19 infection. Such a test may also be valuable in following vaccinated patients to assess the kinetics of anti-SARS-CoV-2 antibody production following inoculation. Multiple serological tests based on serum or plasma have been developed and marketed, with ELISA and lateral flow methods predominating. However, many methods suffer from low sensitivities and specificities [2–6]. Antibodies begin appearing in the first week following the development of symptoms. IgG, IgM, and IgA are detectable with IgA appearing somewhat earlier than IgG and IgM. Most patients seroconvert by 2 weeks following symptoms. Unlike IgA and IgM, IgG persists for several months following infection [7–9]. In a published study of 1,797 Icelandic individuals recovered from qPCR documented COVID-19 disease, 91% were IgG seropositive and antibody levels remained stable for 4 months after initial symptoms [10]. Notably of individuals quarantined due to exposure but untested for virus, with negative qPCR results, tested positive for IgG antibodies. Of 18,609 patients who were both unexposed and asymptomatic, the seropositivity rate was [11]. Since health care systems are burdened with care for COVID-19 patients, having a test that does not require phlebotomy would be extremely beneficial. To that end, investigations have been carried out using home finger prick blood sampling and even some home blood spot testing lateral flow strips [5–7]. However, home finger stick is invasive and not acceptable to some individuals, and requires a health care professional to administer the test to vulnerable individuals such as the elderly and children. In addition, home blood collection tests are less accurate than phlebotomy, with specificities less than 98%. In a low prevalence disease, the positive predictive value for a test with 98% specificity is less than 50% [7, 11]. Saliva is an oral fluid that is obtained easily and non-invasively. Proteomic studies show that the immunoglobulin profile in saliva is nearly identical to that of plasma [12]. Therefore, saliva is an excellent medium for COVID-19 antibody measurement. There are several commercially available collection devices to facilitate saliva collection, stabilization of IgG, and transport. A recently published study demonstrated excellent correlation between levels of COVID-19 antibodies in serum and saliva [13]. In order to be useful in population-based screening and to determine individual immunity in exposed populations, a SARS-CoV-2 antibody test must be highly specific because of the low seroprevalence rate in the population [2, 14]. In addition, the ability to quantify antibody levels is important for vaccine development and in monitoring for waning immunity [2, 14]. The only published saliva based assay for SARS-CoV-2 antibodies had only 89% sensitivity with 98% specificity [13], leading to a positive predictive value of only 49% in a population with a 2% prevalence of COVID-19 exposure. Our goal was to develop a non-invasive saliva based quantitative test for COVID-19 antibodies with exquisite sensitivity. We reviewed existing literature to find the SARS-CoV-2 antigen domain with the highest specificity and the ability to distinguish between the COVID-19 virus and other related Coronaviruses. The S1 domain is the most specific in terms of cross reactivity with other Corona and other respiratory viruses. As recombinant S1 antigen is readily available from at least 2 vendors, we chose the S1 antigen for our assay development. Levels of IgM and IgA deteriorate rapidly following recovery from COVID-19 infection; IgG levels remain detectable for several weeks to months [10]. Since the intended use of our assay is for population-based screening and vaccine efficacy monitoring, we chose to assay IgG only. The Amperial™ technology, formerly known as Electric Field Induced Release and Measurement EFIRM™, is a novel platform capable of performing quantitation of target molecules in both blood and saliva [15]. The device works by immobilizing capture moieties on the surface of an electrode structure for capturing target analytes and then quantifying the target analyte through electrochemically measuring oxidation-reduction between a hydrogen peroxide and tetramethylbenzidine substrate and peroxidase enzyme in a completed assay sandwich. The assay takes place on electrodes packaged in the format of a traditional 96-well microtiter plate, making the assay technique highly compatible and scalable with existing lab liquid handling instruments. We developed quantitative Amperial™ assays for IgG, IgM, and IgA antibodies to the S1 spike protein antigen of SARS-CoV-2. This test is highly sensitive >88% and specific > for patients with COVID-19 infections and correlates well with plasma ELISA analysis. The unique assay described in this article is completely non-invasive, allows home-collection, is quantitative, and has shown no false positives in 667 unexposed individuals, leading to a specificity of at least The assay has strong utility for clinical laboratories as it does not require purification/extraction of the saliva specimen, but the sample can simply be pipetted out of the collection device, diluted, and pipetted to the assay plate. The turnaround time of the assay is also fast, requiring less than 1 hour for a complete assay to be run. The widespread use of this test may be of great value in identifying individuals with prior exposure to SARS-CoV-2, to follow patients longitudinally to determine the kinetics of diminishing antibody concentration, and may be of special value in the longitudinal monitoring of vaccinated individuals to assess continued serologic immunity. Materials and methodsThe schematic of the Amperial™ SARS-CoV-2 IgG antibody is shown in Fig 1. The principle of the Amperial™ platform is that a biomolecule in this case SARS-CoV-2 Spike protein S1 antigen is added to a liquid pyrrole solution that is then pipetted into the bottom of microtiter wells containing a gold electrode at the bottom of each well. After the solution is added to each well, the plate is placed into the Amperial™ Reader and subjected to an electric current leading to polymerization. This procedure results in each well becoming coated with a conducting polymer gel containing the S1 antigen. Following the polymerization, diluted saliva, plasma, or serum is added to the well. Specific anti-S1 antibodies bind to the S1 antigen in the polymer. After rigorous washing procedures, the bound antibody is detected by using biotinylated anti-human IgG and then the signal is amplified by a standard streptavidin / horseradish peroxidase reaction that produces an electric current measured by the Amperial™ Reader in the nanoampere nA scale. The instrument is capable of accurately measuring current in the picoampere pA range, so the measurement is well within the ability of the instrument [13, 14, 16, 17]. The measurement of current rather than optical absorbance, as is done in the typical ELISA, has two important advantages over standard ELISA. Firstly, it allows precise quantitation of the amount of bound antibody and secondly, the measurement of current rather than optical absorbance allows increased sensitivity. Since antibody levels in saliva are lower than in plasma [13, 16], this increased sensitivity is crucial. The precise details of the assay are described in the next paragraph. COVID-19 Spike-1 Antigen Sanyou-Bio, Shanghai, China was diluted to a concentration of μg / mL, added to each well of the microtiter plate, and co-polymerized with pyrrole Sigma-Aldrich, St. Louis, MO onto the bare gold electrodes by applying a cyclic square wave electric field at 350 mV for 1 second and 1100 mV for 1 second. In total, polymerization proceeded for 4 cycles of 2 seconds each. Following this electro-polymerization procedure, 6 wash cycles were performed using 1x PBS with Tween-20 PBS-T using a 96-channel Biotek 405LS plate washer programmed to aspirate and dispense 400 μL of solution per cycle. Following the application of the polymer layer, 30 μL of saliva diluted at a 110 ratio in Casein/PBS Thermo-Fisher, Waltham, MA was pipetted into each well and incubated for 10 minutes at room temperature. Unbound components were removed by performing 6 wash cycles of PBS-T using the plate washer. Biotinylated anti-human IgG secondary antibody Thermofisher, Waltham, MA at a stock concentration of mg / mL was diluted 1500 in Casein/PBS and 30 μL pipetted to the surface of each well and incubated for 10 minutes at room temperature followed by 6 wash cycles using PBS-T. Subsequently, 30 μL of Poly-HRP80 Fitzgerald Industries, Acton, MA at a stock concentration of 2 μg / mL was diluted 125 in Casein/PBS, added to the wells, and incubated at 10 minutes at room temperature. Following a final wash using 6 cycles of PBS-T, current generation is accomplished by pipetting 60 μL of 1-Step Ultra TMB Thermofisher, Waltham, MA to the surface of the electrode and placing the plate into the Amperial™ reader where current is measured at -200 mV for 60 seconds. The current in nA is measured 3 times for each well. The process for reading the entire 96 well plate requires approximately 3 minutes. Plasma quantitative Amperial™ assay for SARS-CoV-2 IgG The protocol is similar to the Amperial™ SARS-CoV-2 IgG antibody for saliva samples. Following the application of the polymer layer, 30 μL of plasma diluted at a 1100 ratio in Casein/PBS Thermo-Fisher, Waltham, MA was pipetted into each well and incubated for 10 minutes at room temperature. The standard curve for plasma contains the following points 300 ng / ml, 150 ng / ml, 75 ng / ml, ng / ml, ng / ml, and 0 ng / ml. Plasma SARS-CoV-2 ELISA assay We purchased FDA EUA ELISA kits EUROIMMUN Anti-SARS-CoV-2 ELISA Assay for detection of IgG antibodies EUROIMMUN US, Mountain Lakes, NJ, Product ID EI 2606–9601 G, Lot E2001513BK. We processed samples exactly as described in the package insert. Human subjects Volunteers, with prior positive qPCR tests for COVID-19 infection or positive antibody tests using currently available FDA EUA-cleared antibody tests were consented via a written consent. Subjects enrolled were all over the age of 18. Subject participants responded to a questionnaire regarding severity of symptoms, onset of symptoms, and method of diagnosis UCLA IRB 06-05-042. Severity of symptoms were self-graded on the following 7-point scale 0 Asymptomatic 1 Mild Barely noticed, perhaps slight fever and cough 2 Moderate felt moderately ill but did not need to seek medical care 3 Sought medical Care but was not admitted to hospital 4 Hospitalized 5 Admitted to ICU 6 Placed on Ventilator A set of 13 paired saliva and plasma samples were provided by the Orasure™ Company. Saliva collection All COVID-19 samples were obtained using the Orasure™ FDA-cleared saliva collection device and used according to manufacturer instructions. The Orasure™ collection device consists of an absorbent pad on the end of a scored plastic wand. The individual places the pad between cheek and gum for a period of 2–5 minutes. Subsequently the wand and pad are placed into a tube containing transport medium, the top of the stick is broken off, and the tube is sealed for transport. The sealed tube is placed into a zip-lock bag and shipped by any standard method. According to the package insert, samples are stable at ambient temperature for 21 days see results below and Orasure™ website. An alternate sample collection method involves the individual swabbing the pad 4 times in the gingival tooth junction prior to placing the pad between the cheek and gum. This method has been shown to improve IgG yield in some patients with low antibody levels personal communication with Orasure Technologies, Inc.. Participant recruitment method Positive samples determined either through a positive SARS-CoV-2 viral test or antibody test were acquired beginning May 2020 to July 2020 via the described Orasure™ Oral Fluid Collection Device Kit previous described. Subjects were recruited into the study via electronic correspondence during the early stages of the COVID-19 pandemic in regions affected by COVID-19 California, Illinois, New York, New Jersey. Subjects are all over the age of 18. Subjects are not representative of the general population. Samples collected pre-2012 were used as controls. Saliva was collected from healthy individual volunteers at meetings of the American Dental Association between 2006 and 2011. Consent was obtained under IRB approval UCLA IRB 06-05-042. Both male and females, mostly non-smokers, 18–80 years of age, and differing ethnicities were included. All subjects were consented prior to collection. Each subject expectorated ~ 5 mL of whole saliva in a 50cc conical tube set on ice. The saliva was processed within 1/2 hour of collection. Samples were spun in a refrigerated centrifuge at 2600 X g for 15 minutes at 4°C. The supernatant cell-free saliva was then pipetted into two-2 mL cryotubes and μL Superase-In Ambion, Austin, TX was added as a preservative. Each tube was inverted to mix. The samples were frozen in dry ice and later stored in -80°C. Sample size and statistical methods Due to the nature of the pandemic and the evolving nature of EUA diagnostics during the early phases of the pandemic, no power calculations were performed for study size but instead the FDA/EUA recommendation of 30 subjects was followed. For components of work that required comparisons between groups, student’s T-test was conducted. p value, corresponds to a 95% confidence or p value, corresponds to 99% confidence. Data analysis performed was using GraphPad Prism Results Linearity Fig 2 demonstrates the dynamic range and linearity of the assay. In these experiments varying amounts of monoclonal human anti-S1 IgG was added to a saliva sample from a healthy volunteer and subjected to the assay. Fig 2 shows a range of to 6 ng/ml. The Y-axis shows nano-amperage measured nA. The X-axis represents spike-in concentrations of IgG. The assay begins to become saturated at about 3 ng / ml. Fig 3 shows dilutions down to ng / ml to ng / ml and shows linearity in that range. This allows us to create a standard curve containing the following points 3 ng / ml, ng / ml, ng / ml, ng / ml, ng / ml, and 0 ng / ml. Fig 2. Dynamic range and linear range of Amperial™ anti-Spike S1 IgG Amount of spike in anti-SARS-CoV-2 IgG in ng / ml. Y-axis Normalized current in nA. Panel A 0–5 ng / ml Panel B ng / ml. Inhibition assay In order to demonstrate the specificity for the assay on actual clinical samples, we used the saliva from 3 recovered patients who had high levels of SARS-CoV-2 antibodies and added exogenous S1 antigen in varying amounts prior to analysis on the Amperial™ assay. The exogenous S1 antigen should compete for binding sites and therefore extinguish the nA signal. Fig 3 shows the results of this experiment. The red, purple, and green represent 3 different patients. The X-axis demonstrates increasing concentration of exogenous S1 added to the saliva before subjecting it to the assay. As shown, saliva pre-incubated with S1 antigen extinguishes the detectable IgG signal proportionately, therefore demonstrating the specificity of the assay to S1 antigen in clinical samples. Matrix effects Since we are be comparing samples collected by various methods, it is vital to determine if any significant matrix effects could interfere with data interpretation. We examined the 3 different collection methods used in this study Expectoration/centrifugation, Orasure™ without swabbing and Orasure™ with swabbing. Two methods of collection using the Orasure™ Oral Fluid Collection Device were tested. The first method non-swabbing collects saliva by placing an absorbent pad into the lower gum area for 2–5 minutes and then placing the saturated collection pad into a preservative collection tube. The second method swabbing adds the step of first gently rubbing the collection pad along gum line, between the gum and cheek, 5 times, before placing the device in the lower gum area for 2–5 minutes, and then immersing the saturated collection pad into the collection tube. Healthy donors n = 5 collected their saliva using these two different methods. The control pre-2012 samples were collected with an expectoration protocol for whole saliva collection falcon tubes, processing centrifuge, stabilization, and storage. Five samples collected by each of the 3 methods and were analyzed in duplicate. The results are shown in Fig 4 under the heading “No spike in.” There are no differences among 3 sample types. We then added monoclonal human anti-S1 IgG to each sample and again ran them in duplicate Fig 4 above caption Spike-in ng / ml IgG. A non-parametric Student t-test was performed with no significant differences between any of the collection methods. Stability The Orasure™ collector is an FDA-cleared device for the analysis of anti-HIV IgG. The package insert describes a 21-day stability at ambient temperature. We wished to establish the stability of anti-COVID-19 IgG using this collector. Passive whole saliva was collected from four healthy individuals using 50 mL falcon tubes and spiked with anti-Spike S1 IgG to reach a final concentration of 300 ng / ml. Aliquots of mL of saliva were placed into 50 mL tubes and then the sponge of the Orasure™ collector was submerged into the saliva for five minutes and processed as described in Methods. The collected saliva was then aliquoted into PCR tubes and left at ambient temperature 21°C for 0, 1, 3, 7, and 14 days before storage at -80°C. After 14 days, samples were thawed and assayed using the anti-Spike S1 IgG Amperial™ assay to assess stability. At 14 days, 95% of the original signal remained, demonstrating the 14-day stability of anti-SARS-CoV-2 antibodies collected in Orasure™ containers see Fig 5. Fig 5. Stability study performed on spike-in of SARS-CoV-2 IgG into healthy saliva specimen using two different methods a research SOP which involves expectoration into a falcon tube and the Orasure™ Oral Fluid collection device.The collect saliva was aliquoted and left at ambient temp for 0, 1, 3, 7, 14 days. Results were normalized relative to the measured assay signal of a sample at day 0. Results show that the sample is stable with no significant degradation for up to 14 days. Specificity and reference range Once we established no significant differences between the tube collection method and the Orasure™ collector method, we analyzed a series of 667 samples collected between 2006 and 2009 at the annual meeting of the American Dental Association. Scatter plots of these data for both nA and ng / ml are shown in Fig 6A and 6B. We established the mean and standard deviation for both raw nA values and concentration in ng / ml. In order to maximize specificity, we selected a reference range > 5 SD above the mean. A 5 sigma level would lead to a specificity of In fact, we have never seen a healthy sample above the 5 sigma level. As will be seen, the sensitivity of the assay remains greater than 88% even with this rigorous specificity. Fig 6. Healthy reference range of Amperial™ saliva anti-SARS-CoV-2 IgG assay of 667 unexposed subjects in A normalized current ΔnA with mean = and cutoff = and B concentration ng / ml with mean = and cutoff = Recovered COVID-19 patients Fig 7 displays the scatter plot for 667 healthy controls and 34 volunteer patients who recovered from COVID-19 infection. All patients were a minimum of 14 days post onset of symptoms and some patients were as many as 15 weeks post symptoms. The 5 sigma cutoff is shown by the green dotted line. A more detailed discussion of the recovered patients appears in the following section. The data show that all healthy patients are negative and 30 of the 34 recovered patients are positive. These data demonstrate a sensitivity of 88% and a specificity of > It is important to note that not all recovered patients have detectable antibody [10] so the 4 patients with undetectable antibody may be biologically negative and not the result of lack of sensitivity of the assay. Fig 8 demonstrates the relationship of anti-S1 IgG levels to severity of symptoms. Table 1 is a tabular summary of these data. All patients who had severity indexes ≥3 sought medical attention, admitted to hospital, admitted to ICU, on ventilator had positive antibody levels. Although 4 patients with mild symptoms had antibody levels in the normal range, both asymptomatic patients had appreciable antibody levels. These patients were close contacts of more severely affected patients. The highest antibody level recorded is severity index level 2 patient moderate symptoms, did not seek medical care. It is important to note that both asymptomatic patients had easily detectable antibody levels in saliva, suggesting this test may be useful in general population screening. Paired saliva and plasma samples We obtained 14 paired, blinded plasma and saliva samples. The plasma was analyzed by an FDA EUA-cleared ELISA test purchased from EUROIMMUN see Methods. The saliva samples, collected in Orasure™ buffer, were analyzed by the Amperial™ assay described in Methods. After unblinding, we discovered 8 recovered COVID patients and 5 healthy patients in this series. All 5 healthy patients were negative in both the saliva and plasma assays. In 7 of the 8 recovered patients, both plasma and saliva tests were positive. There was one sample with a discrepancy between saliva and plasma, with the plasma positive and the saliva in the indeterminate range. The EUROIMMUNE ELISA assay is a semi-quantitative assay and yields an absorbance ratio rather than a quantity. Fig 9 demonstrates the relationship between the saliva quantitative results and plasma absorbance ratio for the paired plasma and saliva samples. There is a clear relationship between the 2 levels, with the higher plasma absorbance ratios associated with higher saliva quantitation. Fig 9. COVID-19 antibody level in paired saliva and plasma of COVID-19 n = 8 subjects in a blinded randomized antibodies level are measured by EUROIMMUN ELISA reported in ratio proportion of OD of calibrator to OD of sample and saliva antibodies are measured by Amperial™ in pg / ml. Green dashed line indicates 5 SD reference range cutoff of Amperial™ test and red dashed line is reference range for EUROIMMUN ELISA. developed a research quality assay to quantify anti-SARS-CoV-2 IgG levels in plasma see Methods. We analyzed the 13 plasma samples using this assay. The results of this experiment are shown in Fig 10. Panel A shows a log / log plot of plasma versus saliva levels showing a clustering with high plasma levels associated with high saliva levels. Panel B shows the box plot of these values, demonstrating that plasma levels are approximately 50X those of saliva. This observation explains the necessity for an extremely sensitive assay such as the Amperial™ assay in order to detect antibodies in saliva. Of note, the publication regarding saliva SARS-CoV-2 IgG detection reports levels of 25–60 mcg / ml, 1000 times less sensitive than our assay. Fig 10. Relationship of plasma anti-SARS-CoV-2 IgG levels to saliva levels measured by Amperial™ assays.A Panel A shows a log / log plot of plasma versus saliva levels showing a clustering of the positive values with high plasma levels associated with high saliva levels on the Amperial™ platform. B Box plot of COVID-19 n = 8 and healthy n = 5 subjects demonstrating that the normalized plasma levels are approximately 50X those of saliva. Longitudinal tracking of antibody levels Three of our volunteers supplied samples at weekly intervals so we could determine the stability of their antibody levels. Results appear in Fig 11. The 5 standard deviation cutoff is again shown with the dashed green line. All 3 patients continued to have detectable levels for more than 12 weeks, with the longest interval of 15 weeks. All tests were positive in all patients and antibody levels in all 3 patients remained clearly positive during the time interval studied. Patients C1 and C3 seem to have a rise in antibody level between 11 and 12 weeks post initial symptoms followed by a return to baseline level. Patient C2 might also have had a spike in antibody levels at 10 weeks. This may be result of the amnestic B-cell population becoming established. There is insufficient data at this time to determine if this is a generalized pattern. CLIA evaluation We performed a full CLIA laboratory developed test evaluation for the Amperial™ COVID-19 IgG Antibody test. The validation assayed 72 unaffected patients and 30 recovered patients and demonstrated 100% sensitivity and specificity. The intra-assay and inter-assay variability were and respectively. DiscussionWe have developed an exquisitely specific, sensitive, non-invasive saliva based quantitative assay for anti-SARS-CoV-2 IgG antibodies. Our goal was to create a quantitative assay with sufficient positive predictive value to be useful to inform individuals regarding previous infection with COVID-19. By establishing a reference range of 5 sigma above than the mean we have a theoretical analytical specificity of We plan to repeat the analysis of all positive samples to further increase analytical specificity. Since our test is non-invasive with home-collection we can also offer repeat testing on a second sample to further increase specificity. These procedures will minimize the false positives due to purely technical issues. There is still the possibility of biological false positives, however, due to cross reactivity with other infectious or environmental agents. The S1 antigen appears to be specific for SARS-CoV-2 [2, 3, 10] and in our series of 667 samples collected prior to 2019 we observed no false positive results. We cannot predict the eventual clinical specificity of this assay. At a minimum, the specificity is 667 / 668 or assuming the next control sample tested would be a false positive, but the specificity is likely to be higher. Our current sensitivity is 100% for patients with symptoms severe enough to seek medical care. For all patients, including mildly asymptomatic patients, our clinical sensitivity is 88%. Since the Amperial™ assay only requires 6 μL of collection fluid, several assays can be performed from the same sample. This allows all positives to be repeated to confirm the positive results and further increase the specificity of the assay. We will offer testing of a second, independent sample for all patients testing positive. Since saliva collection is easily be performed at home, obtaining a second sample is not difficult. For any laboratory test, the PPV is proportional to the prevalence of positivity in the population. A recent study demonstrated a prevalence of between to 6% in Britain [17]. Using the minimum specificity of and a prevalence of 6% the Amperial™ saliva assay would have a minimum PPV of 96%. In contrast, a published saliva antibody detection assay reported a specificity of 98% with a similar sensitivity 89%. This specificity leads to PPV of only 69% making it an ineffective tool for population screening. Our data demonstrate that the Imperial™ assay is appropriate for longitudinal screening of antibody levels, a particular utility in vaccine trials and in population monitoring following mass immunization. Since this assay is quantitative and levels appear to be stable with time, patients may be monitored from home at frequent intervals. If antibodies raised in response to vaccination do not include IgG antibodies to S1 antigen, it is easy to rapidly develop Amperial™ antibody tests to any antigen. This requires adding the new antigen to the pyrrole solution and does not require significant alteration of assay conditions. A particular advantage of this assay is convenience. The Orasure™ collector is simple and easy to use and does not require professional monitoring for adequate collection. Home collection relieves the burden to an already stressed health care system. Vulnerable populations such as children and the elderly can be guided through the collection process by parents or other adults. It is possible to obtain repeat samples to confirm positives and to perform longitudinal testing since the only requirement for testing is shipping the collecting kit. The Amperial™ IgG test is plate-based and high-throughput. An entire plate is easily processed in 2 hours, leading to rapid turnaround time once the sample enters the laboratory. There is no pre-processing of the sample required; samples are taken directly from the collection vial and placed into the assay. With standard liquid handlers, the assay may be easily automated allowing for extremely high-throughput since the Amperial™ reader is only required for the polymerization step of less than a minute at the beginning of the assay and 3 minutes for the measurement phase at the end of the assay. Published data [13] and our own demonstrate a correlation between blood results and saliva results indicating that the IgG present in saliva is most likely derived from the plasma through filtration. Our data shows that saliva IgG levels are approximately 50-fold less than those in plasma necessitating a highly sensitive assay in order to detect the IgG levels in saliva. There is some discussion in the literature of the role antibody testing may have in managing the COVID-19 epidemic. Alter and Seder published an editorial in the New England Journal of Medicine arguing, “Contrary to recent reports suggesting that SARS-CoV-2 RNA testing alone, in the absence of antibodies, will be sufficient to track and contain the pandemic, the cost, complexity, and transient nature of RNA testing for pathogen detection render it an incomplete metric of viral spread at the population level. Instead, the accurate assessment of antibodies during a pandemic can provide important population-based data on pathogen exposure, facilitate an understanding of the role of antibodies in protective immunity, and guide vaccine development [14]”. ConclusionIn this article, we describe the development of a non-invasive, home collection based, exquisitely specific, and acceptably sensitive test for the presence of anti-SARS-CoV-2 antibodies in saliva. This may be an important tool in controlling the pandemic and facilitating and understanding of the role of antibody production in COVID-19 immunity. Longitudinal monitoring of anti-SARS-CoV-2 IgG levels could also play a valuable role in vaccine development and deployment by allowing longitudinal quantitative assessment of antibody levels. If the presence of detectable anti-COVID-19 IgG is shown to be an indicator of immunity to reinfection, measurement of these antibodies could allow individuals to safely return to work, school and community. The Amperial™ SARS-CoV-2 assay fulfills the requirements for all of these applications. References1. Guan W, Ni Z, Hu Y, Liang W, Ou C, He J, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. New Eng J Med. 2020 Apr;382181708–20. pmid32109013 View Article PubMed/NCBI Google Scholar 2. Interim Guidelines for COVID-19 Antibody Testing. Center for Disease Control and Prevention. 2020 Aug 1. [Cited 2020 Nov 5] 3. Hoffman T, Nissen K, Krambach J, Ronnberg B, Akaberi D, Esmaeilzadeh , et al. Evaluation of a COVID-19 IgM and IgG rapid test; an efficient tool for assessment of past exposure to SARS-CoV-2. Infection Ecology and Epidemiology. 2020 Jan 1;1011754538. pmid32363011 View Article PubMed/NCBI Google Scholar 4. Montesinos I, Gruson D, Kabamba B, Dahma H, Wijngaert S, Reza S, et al. Evaluation of two automated and three rapid lateral flow immunoassays for the detection of SARS CoV-2 antibodies. Journal of Clinical Virology. 2020 Jul;128104413. pmid32403010 View Article PubMed/NCBI Google Scholar 5. Döhla M, Boesecke C, Schulte B, Diegmann C, Sib E, Richter E, et al. Rapid point-of-care testing for SARS-CoV-2 in a community screening setting shows low sensitivity. Public Health. 2020 May;182170–172. pmid32334183 View Article PubMed/NCBI Google Scholar 6. Rashid Z, Othman S, Samat M, Ali U, Wong K. Diagnostic performance of COVID-19 serology assays, Malaysian J Pathol, 2020 Apr;42113–21. View Article Google Scholar 7. Thevis M, Knoop A, Schafer M, Dufaux B, Schrader Y, Thomas A, et al. Can dried blood spots DBS contribute to conducting comprehensive SARS-CoV-2 antibody tests? Drug Test Analy. 2020 Jul;127994–7. pmid32386354 View Article PubMed/NCBI Google Scholar 8. Sun B, Feng Y, Mo X, Zheng P, Wang Q, Li P, et al. Kinetics of SARS-CoV-2 specific IgM and IgG responses in COVID-19 patients. Emerging Microbes and Infections. 2020 Jan 1;91940–948. pmid32357808 View Article PubMed/NCBI Google Scholar 9. Shi Y, Wang Y, Shao C, Huang J, Gan J, Huang X, et al. COVID-19 infection the perspectives on immune response. Cell Death and Differentiation. 2020 May;275 1451–1454. pmid32205856 View Article PubMed/NCBI Google Scholar 10. Gudbjartsson D, Norddahl G, Melsted P, Gunnarsdottir K, Holm H, Eythorsson E, et al. Humeral immune response to SARS-CoV-2 in Iceland. N Engl J Med. 2020 Oct 29;383181724–1734. pmid32871063 View Article PubMed/NCBI Google Scholar 11. Okba N, Muller M, Li W, Wang C, GeurtsvanKessel C, Corman V, et al. Severe Acute Respiratory Syndrome Coronavirus 2 –Specific Antibody Responses in Coronavirus Disease Patients. Emerg Infect Dis. 2020 Jul;26 71478–88. pmid32267220 View Article PubMed/NCBI Google Scholar 12. Hettegger P, Huber J, Pabecker K, Soldo R, Kegler U, Nöhammer C, et al. High similarity of IgG antibody profiles in blood and saliva opens opportunities for saliva based serology. PLoS ONE. 2019 Jun 20;146e0218456. pmid31220138 View Article PubMed/NCBI Google Scholar 13. Isho B, Abe KT, Zuo M, Jamal A, Rathod B, Wang J, et al. Persistence of serum and saliva antibody responses to SARS-CoV-2 spike antigens in COVID-19 patients. Sci Immunol. 2020 Oct 8;552eabe5511. pmid33033173 View Article PubMed/NCBI Google Scholar 14. Alter G, Seder R. The power of Antibody-Based Surveillance. N Engl J Med. 2020 Oct 29;383181782–1784. pmid32871061 View Article PubMed/NCBI Google Scholar 15. Wei F, Patel P, Liao W, Chaudhry K, Zhang L, Arellano-Garcia M, et al. Electrochemical Sensor for Multiplex Biomarkers Detection. Clinical Cancer Research. 2009;15 4446–4452. pmid19509137 View Article PubMed/NCBI Google Scholar 16. 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ProteinS pada SARS-CoV-2 memiliki ikatan yang kuat dengan reseptor ACE2 pada manusia, (Wan et al., 2020), sehingga virus tersebut mudah menginfeksi manusia. Kode PDB Reseptor ACE2 yang digunakan adalah 1r42 (Gambar 3). Pemilihan ligan terbaik yang dapat menghambat interaksi antara Protein S dari SARS-CoV-2 dengan

The development timeline of COVID-19 vaccines is unprecedented, with more than 300 vaccine developers active worldwide. Vaccine candidates developed with various technology platforms targeting different epitopes of SARS-CoV-2 are in the pipeline. Vaccine developers are using a range of immunoassays with different readouts to measure immune responses after vaccination, making comparisons of the immunogenicity of different COVID-19 vaccine candidates April, 2020, in a joint effort, the Coalition for Epidemic Preparedness Innovations CEPI, the National Institute for Biological Standards and Control NIBSC, and WHO provided vaccine developers and the entire scientific community with a research reagent for an anti-SARS-CoV-2 antibody. The availability of this material was crucial for facilitating the development of diagnostics, vaccines, and therapeutic preparations. This effort was an initial response when NIBSC, in its capacity as a WHO collaborating centre, was working on the preparation of the WHO International Standards. This work included a collaborative study that was launched in July, 2020, to test serum samples and plasma samples sourced from convalescent patients with the aim of selecting the most suitable candidate material for the WHO International Standards for anti-SARS-CoV-2 immunoglobulin. The study involved 44 laboratories from 15 countries and the use of live and pseudotype-based neutralisation assays, ELISA, rapid tests, and other methods. The outcomes of the study were submitted to WHO in November, 2020. The inter-laboratory variation was reduced more than 50 times for neutralisation and 2000 times for ELISA when assay values were reported relative to the International International Standard and International Reference Panel for anti-SARS-CoV-2 immunoglobulins were adopted by the WHO Expert Committee on Biological Standardization on Dec 10, WHO International Standard for anti-SARS-CoV-2 Scholar The International Standard allows the accurate calibration of assays to an arbitrary unit, thereby reducing inter-laboratory variation and creating a common language for reporting data. The International Standard is based on pooled human plasma from convalescent patients, which is lyophilised in ampoules, with an assigned unit of 250 international units IU per ampoule for neutralising activity. For binding assays, a unit of 1000 binding antibody units BAU per mL can be used to assist the comparison of assays detecting the same class of immunoglobulins with the same specificity eg, anti-receptor-binding domain IgG, anti-N IgM, etc The International Standard is available in the NIBSC have been launched for the harmonisation of immune response assessment across COVID-19 vaccine candidates, including the CEPI Global Centralised Laboratory for Epidemic Preparedness InnovationsCEPI establishes global network of laboratories to centralise assessment of COVID-19 vaccine Scholar CEPI centralised laboratories will achieve harmonisation of the results from different vaccine clinical trials with the use of common standard operating procedures and the same crucial reagents, including a working standard calibrated to the international basic tool for any harmonisation is the global use of an International Standard and IU to which assay data need to be calibrated with the use of a reliable method. It is therefore crucial that the International Standard is properly used by all vaccine developers, national reference laboratories, and academic groups worldwide, and that immunogenicity results are reported as an international standard unit IU/mL for neutralising antibodies and BAU/mL for binding assay formats.In this manner, the results from clinical trials expressed in IU would allow for the comparison of the immune responses after natural infection and induced by various vaccine candidates. This comparison is particularly important for the identification of correlates of protection against COVID-19; should neutralising antibodies be further supported as a component of the protective response, the expression of antibody responses in IU/mL is essential to gather a consensus from several clinical trials and other studies on the titre required for the correlate of protection against SARS-2-CoV has not yet been unequivocally defined, antibodies are likely to be at least part of the protective response. The effect of new variants on the evaluation of antibodies is obvious and unequivocal comparisons are required. Reporting the immunological responses from vaccine clinical trials against the International Standard is essential for the evaluation of clinical data submitted to national regulatory authorities as well as to WHO for emergency use listing, especially as placebo-controlled efficacy studies become operationally unfeasible. There will be a substantial effect on the use of the International Standard if regulatory authorities worldwide request data in IU/mL or BAU/mL. We also encourage journal editors and peer reviewers to ensure that the international standard is used as the benchmark in publications and that data from serology assays are reported in International Standard declare no competing TT Cramer JP Chen R Mayhew S Evolution of the COVID-19 vaccine development Rev Drug Discov. 2020; 19 WHO International Standard for anti-SARS-CoV-2 for Epidemic Preparedness InnovationsCEPI establishes global network of laboratories to centralise assessment of COVID-19 vaccine infoPublication historyPublished March 23, 2021IdentificationDOI Copyright © 2021 Published by Elsevier Ltd. All rights this article on ScienceDirectView Large ImageDownload Hi-res image Download .PPT

Persyaratan& Jenis Sampel Serum Stabilitas Sampel * 2 hari pada suhu 15-25 C 7 hari pada suhu 2-8 C 1 bulan pada suhu = (-20)C (vena) Persiapan Pasien Lakukan pemeriksaan Anti SARS-CoV-2 IgG Kuantitatif pada Senin - Sabtu pukul 08.00 - 11.00 waktu setempat Hari Kerja Metode CMIA (Chemiluminescent Microparticle Immunoassay) Nilai Rujukan Tempat Rujukan Catatan Brief Communication Published 29 April 2020 Bai-Zhong Liu2 na1, Hai-Jun Deng ORCID na1, Gui-Cheng Wu3,4 na1, Kun Deng5 na1, Yao-Kai Chen6 na1, Pu Liao7, Jing-Fu Qiu8, Yong Lin ORCID Xue-Fei Cai1, De-Qiang Wang1, Yuan Hu1, Ji-Hua Ren1, Ni Tang1, Yin-Yin Xu2, Li-Hua Yu2, Zhan Mo2, Fang Gong2, Xiao-Li Zhang2, Wen-Guang Tian2, Li Hu2, Xian-Xiang Zhang3,4, Jiang-Lin Xiang3,4, Hong-Xin Du3,4, Hua-Wen Liu3,4, Chun-Hui Lang3,4, Xiao-He Luo3,4, Shao-Bo Wu3,4, Xiao-Ping Cui3,4, Zheng Zhou3,4, Man-Man Zhu5, Jing Wang6, Cheng-Jun Xue6, Xiao-Feng Li6, Li Wang6, Zhi-Jie Li7, Kun Wang7, Chang-Chun Niu7, Qing-Jun Yang7, Xiao-Jun Tang8, Yong Zhang ORCID Xia-Mao Liu9, Jin-Jing Li9, De-Chun Zhang10, Fan Zhang10, Ping Liu11, Jun Yuan1, Qin Li12, Jie-Li Hu ORCID Juan Chen ORCID & …Ai-Long Huang ORCID Nature Medicine volume 26, pages 845–848 2020Cite this article 824k Accesses 5536 Citations 4038 Altmetric Metrics details Subjects AbstractWe report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G IgG. Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT–PCR results and for the identification of asymptomatic infections. MainThe continued spread of coronavirus disease 2019 COVID-19 has prompted widespread concern around the world, and the World Health Organization WHO, on 11 March 2020, declared COVID-19 a pandemic. Studies on severe acute respiratory syndrome SARS and Middle East respiratory syndrome MERS showed that virus-specific antibodies were detectable in 80–100% of patients at 2 weeks after symptom onset1,2,3,4,5,6. Currently, the antibody responses against SARS-CoV-2 remain poorly understood and the clinical utility of serological testing is total of 285 patients with COVID-19 were enrolled in this study from three designated hospitals; of these patients, 70 had sequential samples available. The characteristics of these patients are summarized in Supplementary Tables 1 and 2. We validated and used a magnetic chemiluminescence enzyme immunoassay MCLIA for virus-specific antibody detection Extended Data Fig. 1a–d and Supplementary Table 3. Serum samples from patients with COVID-19 showed no cross-binding to the S1 subunit of the SARS-CoV spike antigen. However, we did observe some cross-reactivity of serum samples from patients with COVID-19 to nucleocapsid antigens of SARS-CoV Extended Data Fig. 1e. The proportion of patients with positive virus-specific IgG reached 100% approximately 17–19 days after symptom onset, while the proportion of patients with positive virus-specific IgM reached a peak of approximately 20–22 days after symptom onset Fig. 1a and Methods. During the first 3 weeks after symptom onset, there were increases in virus-specific IgG and IgM antibody titers Fig. 1b. However, IgM showed a slight decrease in the >3-week group compared to the ≤3-week group Fig. 1b. IgG and IgM titers in the severe group were higher than those in the non-severe group, although a significant difference was only observed in IgG titer in the 2-week post-symptom onset group Fig. 1c, P = 1 Antibody responses against Graph of positive rates of virus-specific IgG and IgM versus days after symptom onset in 363 serum samples from 262 patients. b, Levels of antibodies against SARS-CoV-2 in patients at different times after symptom onset. c, Comparison of the level of antibodies against SARS-CoV-2 between severe and non-severe patients. The boxplots in b and c show medians middle line and third and first quartiles boxes, while the whiskers show the interquartile range IQR above and below the box. Numbers of patients N are shown underneath. P values were determined with unpaired, two-sided Mann–Whitney DataFull size imageSixty-three patients with confirmed COVID-19 were followed up until discharge. Serum samples were collected at 3-day intervals. Among these, the overall seroconversion rate was 61/63 over the follow-up period. Two patients, a mother and daughter, maintained IgG- and IgM-negative status during hospitalization. Serological courses could be followed for 26 patients who were initially seronegative and then underwent seroconversion during the observation period. All these patients achieved seroconversion of IgG or IgM within 20 days after symptom onset. The median day of seroconversion for both IgG and IgM was 13 days post symptom onset. Three types of seroconversion were observed synchronous seroconversion of IgG and IgM nine patients, IgM seroconversion earlier than that of IgG seven patients and IgM seroconversion later than that of IgG ten patients Fig. 2a. Longitudinal antibody changes in six representative patients of the three types of seroconversion are shown in Fig. 2b–d and Extended Data Fig. 2a– 2 Seroconversion time of the antibodies against Seroconversion type of 26 patients who were initially seronegative during the observation period. The days of seroconversion for each patient are plotted. b–d, Six representative examples of the three seroconversion type synchronous seroconversion of IgG and IgM b, IgM seroconversion earlier than that of IgG c and IgM seroconversion later than that of IgG c.Full size imageIgG levels in the 19 patients who underwent IgG seroconversion during hospitalization plateaued 6 days after the first positive IgG measurement Extended Data Fig. 3. Plateau IgG levels varied widely more than 20-fold across patients. IgM also showed a similar profile of dynamic changes Extended Data Fig. 4. We found no association between plateau IgG levels and the clinical characteristics of the patients Extended Data Fig. 5a–d. We next analyzed whether the criteria for confirmation of MERS-CoV infection recommended by WHO, including 1 seroconversion or 2 a fourfold increase in IgG-specific antibody titers, are suitable for the diagnosis of COVID-19 using paired samples from 41 patients. The initial sample was collected in the first week of illness and the second was collected 2–3 weeks later. Of the patients whose IgG was initially seronegative in the first week of illness, 21/41 underwent seroconversion. A total of 18 patients were initially seropositive in the first week of illness; of these, eight patients had a fourfold increase in virus-specific IgG titers Extended Data Fig. 6. Overall, 29/41 of the patients with COVID-19 met the criteria of IgG seroconversion and/or fourfold increase or greater in the IgG investigate whether serology testing could help identify patients with COVID-19, we screened 52 suspected cases in patients who displayed symptoms of COVID-19 or abnormal radiological findings and for whom testing for viral RNA was negative in at least two sequential samples. Of the 52 suspected cases, four had virus-specific IgG or IgM in the initial samples Extended Data Fig. 7. Patient 3 had a greater than fourfold increase in IgG titer 3 days after the initial serology testing. Interestingly, patient 3 also tested positive for viral infection by polymerase chain reaction with reverse transcription RT–PCR between the two antibody measurements. IgM titer increased over three sequential samples from patient 1 1 was defined as positive and S/CO ≤ 1 as of IgG and IgM against SARS-CoV-2To measure the level of IgG and IgM against SARS-CoV-2, serum samples were collected from the patients. All serum samples were inactivated at 56 °C for 30 min and stored at −20 °C before testing. IgG and IgM against SARS-CoV-2 in plasma samples were tested using MCLIA kits supplied by Bioscience Co. approved by the China National Medical Products Administration; approval numbers 20203400183IgG and 20203400182IgM, according to the manufacturer’s instructions. MCLIA for IgG or IgM detection was developed based on a double-antibody sandwich immunoassay. The recombinant antigens containing the nucleoprotein and a peptide from the spike protein of SARS-CoV-2 were conjugated with FITC and immobilized on anti-FITC antibody-conjugated magnetic particles. Alkaline phosphatase conjugated anti-human IgG/IgM antibody was used as the detection antibody. The tests were conducted on an automated magnetic chemiluminescence analyzer Axceed 260, Bioscience according to the manufacturer’s instructions. All tests were performed under strict biosafety conditions. The antibody titer was tested once per serum sample. Antibody levels are presented as the measured chemiluminescence values divided by the cutoff S/CO. The cutoff value of this test was defined by receiver operating characteristic curves. Antibody levels in the figures were calculated as log2S/CO + 1.Performance evaluation of the SARS-CoV-2-specific IgG/IgM detection assayThe precision and reproducibility of the MCLIA kits were first evaluated by the National Institutes for Food and Drug Control. Moreover, 30 serum samples from patients with COVID-19 showing different titers of IgG range and IgM range were tested. Each individual sample was tested in three independent experiments, and the coefficient of variation CV was used to evaluate the precision of the assay. Finally, 46 serum samples from patients with COVID-19 were assessed using different batches of the diagnostic kit for SARS-CoV-2-specific IgG or IgM antibody; reproducibility was calculated based on the results from two batch of antigens from SARS-CoV and SARS-CoV-2Two recombinant SARS-CoV nucleocapsid N proteins from two different sources Sino Biological, cat. no. 40143-V08B; Biorbyt, cat. no. orb82478, the recombinant S1 subunit of the SARS-CoV spike Sino Biological, cat. no. 40150-V08B1 and the homemade recombinant N protein of SARS-CoV-2 were used in a chemiluminescence enzyme immunoassay CLEIA, respectively. The concentration of antigens used for plate coating was μg ml−1. The dilution of alkaline phosphatase conjugated goat anti-human IgG antibody was 12,500. Five serum samples from patients with COVID-19 and five serum samples from healthy controls were diluted 150 and tested using CLEIA assays. The binding ability of antibody to antigen in a sample was measured in relative luminescence analysesContinuous variables are expressed as the median IQR and were compared with the Mann–Whitney U-test. Categorical variables are expressed as numbers % and were compared by Fisher’s exact test. A P value of < was considered statistically significant. Statistical analyses were performed using R software, version approvalThe study was approved by the Ethics Commission of Chongqing Medical University ref. no. 2020003. Written informed consent was waived by the Ethics Commission of the designated hospital for emerging infectious SummaryFurther information on research design is available in the Nature Research Reporting Summary linked to this article. Data availabilityRaw data in this study are provided in the Supplementary Dataset. Additional supporting data are available from the corresponding authors on request. 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This work was supported by the Emergency Project from the Science & Technology Commission of Chongqing and a Major National S&T Program grant 2017ZX10202203 and 2017ZX10302201 from the Science & Technology Commission of informationAuthor notesThese authors contributed equally Quan-Xin Long, Bai-Zhong Liu, Hai-Jun Deng, Gui-Cheng Wu, Kun Deng, Yao-Kai and AffiliationsKey Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, ChinaQuan-Xin Long, Hai-Jun Deng, Yong Lin, Xue-Fei Cai, De-Qiang Wang, Yuan Hu, Ji-Hua Ren, Ni Tang, Jun Yuan, Jie-Li Hu, Juan Chen & Ai-Long HuangYongchuan Hospital Affiliated to Chongqing Medical University, Chongqing, ChinaBai-Zhong Liu, Yin-Yin Xu, Li-Hua Yu, Zhan Mo, Fang Gong, Xiao-Li Zhang, Wen-Guang Tian & Li HuChongqing University Three Gorges Hospital, Chongqing, ChinaGui-Cheng Wu, Xian-Xiang Zhang, Jiang-Lin Xiang, Hong-Xin Du, Hua-Wen Liu, Chun-Hui Lang, Xiao-He Luo, Shao-Bo Wu, Xiao-Ping Cui & Zheng ZhouChongqing Three Gorges Central Hospital, Chongqing, ChinaGui-Cheng Wu, Xian-Xiang Zhang, Jiang-Lin Xiang, Hong-Xin Du, Hua-Wen Liu, Chun-Hui Lang, Xiao-He Luo, Shao-Bo Wu, Xiao-Ping Cui & Zheng ZhouThe Third Hospital Affiliated to Chongqing Medical University, Chongqing, ChinaKun Deng & Man-Man ZhuDivision of Infectious Diseases, Chongqing Public Health Medical Center, Chongqing, ChinaYao-Kai Chen, Jing Wang, Cheng-Jun Xue, Xiao-Feng Li & Li WangLaboratory Department, Chongqing People’s Hospital, Chongqing, ChinaPu Liao, Zhi-Jie Li, Kun Wang, Chang-Chun Niu & Qing-Jun YangSchool of Public Health and Management, Chongqing Medical University, Chongqing, ChinaJing-Fu Qiu, Xiao-Jun Tang & Yong ZhangThe Second Affiliated Hospital of Chongqing Medical University, Chongqing, ChinaXia-Mao Liu & Jin-Jing LiWanzhou People’s Hospital, Chongqing, ChinaDe-Chun Zhang & Fan ZhangBioScience Co. Ltd, Chongqing, ChinaPing LiuChongqing Center for Disease Control and Prevention, Chongqing, ChinaQin LiAuthorsQuan-Xin LongYou can also search for this author in PubMed Google ScholarBai-Zhong LiuYou can also search for this author in PubMed Google ScholarHai-Jun DengYou can also search for this author in PubMed Google ScholarGui-Cheng WuYou can also search for this author in PubMed Google ScholarKun DengYou can also search for this author in PubMed Google ScholarYao-Kai ChenYou can also search for this author in PubMed Google ScholarPu LiaoYou can also search for this author in PubMed Google ScholarJing-Fu QiuYou can also search for this author in PubMed Google ScholarYong LinYou can also search for this author in PubMed Google ScholarXue-Fei CaiYou can also search for this author in PubMed Google ScholarDe-Qiang WangYou can also search for this author in PubMed Google ScholarYuan HuYou can also search for this author in PubMed Google ScholarJi-Hua RenYou can also search for this author in PubMed Google ScholarNi TangYou can also search for this author in PubMed Google ScholarYin-Yin XuYou can also search for this author in PubMed Google ScholarLi-Hua YuYou can also search for this author in PubMed Google ScholarZhan MoYou can also search for this author in PubMed Google ScholarFang GongYou can also search for this author in PubMed Google ScholarXiao-Li ZhangYou can also search for this author in PubMed Google ScholarWen-Guang TianYou can also search for this author in PubMed Google ScholarLi HuYou can also search for this author in PubMed Google ScholarXian-Xiang ZhangYou can also search for this author in PubMed Google ScholarJiang-Lin XiangYou can also search for this author in PubMed Google ScholarHong-Xin DuYou can also search for this author in PubMed Google ScholarHua-Wen LiuYou can also search for this author in PubMed Google ScholarChun-Hui LangYou can also search for this author in PubMed Google ScholarXiao-He LuoYou can also search for this author in PubMed Google ScholarShao-Bo WuYou can also search for this author in PubMed Google ScholarXiao-Ping CuiYou can also search for this author in PubMed Google ScholarZheng ZhouYou can also search for this author in PubMed Google ScholarMan-Man ZhuYou can also search for this author in PubMed Google ScholarJing WangYou can also search for this author in PubMed Google ScholarCheng-Jun XueYou can also search for this author in PubMed Google ScholarXiao-Feng LiYou can also search for this author in PubMed Google ScholarLi WangYou can also search for this author in PubMed Google ScholarZhi-Jie LiYou can also search for this author in PubMed Google ScholarKun WangYou can also search for this author in PubMed Google ScholarChang-Chun NiuYou can also search for this author in PubMed Google ScholarQing-Jun YangYou can also search for this author in PubMed Google ScholarXiao-Jun TangYou can also search for this author in PubMed Google ScholarYong ZhangYou can also search for this author in PubMed Google ScholarXia-Mao LiuYou can also search for this author in PubMed Google ScholarJin-Jing LiYou can also search for this author in PubMed Google ScholarDe-Chun ZhangYou can also search for this author in PubMed Google ScholarFan ZhangYou can also search for this author in PubMed Google ScholarPing LiuYou can also search for this author in PubMed Google ScholarJun YuanYou can also search for this author in PubMed Google ScholarQin LiYou can also search for this author in PubMed Google ScholarJie-Li HuYou can also search for this author in PubMed Google ScholarJuan ChenYou can also search for this author in PubMed Google ScholarAi-Long HuangYou can also search for this author in PubMed Google ScholarContributionsConceptualization was provided by The methodology was developed by P. Liu, and Investigations were carried out by and The original draft of the manuscript was written by and Review and editing of the manuscript were carried out by and Funding acquisition was performed by and Resources were provided by P. Liao, . and provided authorsCorrespondence to Jie-Li Hu, Juan Chen or Ai-Long declarations Competing interests The authors declare no competing interests. Additional informationPeer review information Saheli Sadanand was the primary editor on this article and managed its editorial process and peer review in collaboration with the rest of the editorial note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional dataExtended Data Fig. 1 The performance evaluation of the SARS-CoV-2 specific IgG/IgM detection Thirty serum sample from COVID-19 patients showing different titers of IgG a range from to and IgM b range from to were tested. Each individual sample was tested in three independent experiment. CVs of titers of certain sample were calculated and presented. c,d. The correlation analysis of IgG and IgM titers serum samples from COVID-19 patients from 2 independent experiment. Forty-six serum samples from COVID-19 patients were detected using different batches of diagnostic kit for SARS-CoV-2 IgG c or IgM d antibody. Pearson correlation coefficients R are depicted in plots. For IgG, r = p = For IgM, r = p = e. The reactivity between COVID-19 patient serums N = 5 and SARS-CoV S1, N two sources and SARS-CoV-2 N protein were measured by ELISA. Serum samples from COVID-19 patients showed no cross-binding to SARS-CoV S1 antigen, while the reactivity between COVID-19 patient serums and SARS-CoV N antigen from different sources was inconsistent. Source Data Extended Data Fig. 2 Three types of Patients with a synchronous seroconversion of IgG and IgM N = 7. b. Seroconversion for IgG occurred later than that for IgMN = 5. c. Seroconversion for IgG occurred earlier than that for IgM N = 8.Extended Data Fig. 3 Dynamic changes of the SARS-CoV-2 specific course of the virus-specific IgG level in 19 patients experienced IgG titer plateau. IgG in each patient reached plateau within 6 days since IgG became Data Fig. 4 Dynamic changes of the SARS-CoV-2 specific course of the virus-specific IgM level in 20 patients experienced IgM titer plateau. IgM in each patient reached plateau within 6 days since IgM became Data Fig. 5 The association between the IgG levels at the plateau and clinical characteristics of the COVID-19 No significant difference in the IgG levels at the plateau was found between < 60 y group N = 11 and ≥ 60 y group N = 9. Unpaired, two-sided Mann-Whitney U test, p = b–d. No association was found between the IgG levels at the plateau and lymphocyte count b or CRP c or hospital stay d of the patients N = 20. Pearson correlation coefficients r and p value are depicted in plots. Source Data Extended Data Fig. 6 The assessment of MERS serological criteria for assessment of MERS serological criteria for COVID-19 confirmation were carried out in 41 patients with sequential samples. All 41 patients were classified into three groups based on IgG change from sequential samples, including 1 seroconversion, 2 fold change ≥ 4-fold in paired samples, 3 Data Fig. 7 Serology testing in identification of COVID-19 from 52 suspected of symptom onset, RT-PCR and serology testing in 4 cases developing positive IgG or/and IgM were Data Fig. 8 Serological survey in close contacts with COVID-19 cluster of 164 close contacts of known COVID-19 patients were tested by RT-PCR followed by serology testing. Serum samples were collected from these 164 individuals for antibody tests approximately 30 days after informationSource dataRights and permissionsAbout this articleCite this articleLong, QX., Liu, BZ., Deng, HJ. et al. Antibody responses to SARS-CoV-2 in patients with COVID-19. Nat Med 26, 845–848 2020. citationReceived 24 March 2020Accepted 22 April 2020Published 29 April 2020Issue Date June 2020DOI This article is cited by AntiSARS CoV-2 atau Antibodi Kualitatif mendeteksi antibodi spesifik terhadap protein Nucleocapsid (N) pada virus SARS-COV-2. Pemeriksaan Anti SARS CoV-2 dengan spesifisitas 99.8% minimal risiko reaksi silang dengan jenis flu umum atau varian lain Corona virus HKU1, NL63, OC43 atau 229E. Anti-HBc IgM, Kuantitatif. Fungsi Klinis

Petugas memeriksa beberapa sampel PCR COVID-19 ilustrasi. JAKARTA - Pendistribusian vaksin SARS-CoV-2 alias Covid-19 tengah berlangsung. Di tengah kondisi itu, banyak pertanyaan bermunculan terkait seberapa besar kekebalan tubuh seseorang yang pernah terpapar Covid-19. Menurut Muhammad Irhamsyah, dokter spesialis patologi di Klinik Primaya Hospital Bekasi Barat dan Bekasi Timur, ada metode untuk memeriksanya. Kekebalan tubuh terhadap Covid-19 bisa diketahui melalui tes antibodi SARS-CoV-2 kuantitatif. "Pemeriksaan ini dapat dilakukan pada orang-orang yang pernah terinfeksi Covid-19, orang yang sudah mendapatkan vaksinasi, serta dapat digunakan untuk mengukur antibodi pada donor plasma konvalesen yang akan ditransfusikan," ujar Irhamsyah. Tes mendeteksi protein yang disebut antibodi, khususnya antibodi spesifik terhadap SARS-CoV-2. Prinsipnya menggunakan pemeriksaan laboratorium imunoserologi pada sebuah alat automatik autoanalyzer untuk mendeteksi antibodi itu. Pemeriksaan ini biasa disebut dengan ECLIA Electro chemiluminescence immunoassay. ECLIA mendeteksi, mengikat, serta mengukur antibodi netralisasi, yaitu antibodi yang berikatan spesifik pada struktur protein Spike SARS-CoV-2. Protein itu terdapat pada permukaan virus Covid-19 sebelum memasuki sel-sel pada tubuh. Pengukuran menggunakan label-label yang berikatan spesifik dengan antibodi netralisasi. Jenis sampel yang digunakan yakni sampel serum dan plasma. BACA JUGA Ikuti News Analysis News Analysis Isu-Isu Terkini Perspektif Klik di Sini

Duringour current vaccination efforts, assays detecting anti-SARS-CoV-2 antibodies are key to monitoring the success of our vaccination strategy. Early assays measuring SARS-CoV-2-specific antibodies were designed to distinguish between naïve and infected individuals. These were usually developed as qualitative rather than quantitative assays

Yukkcari tahu dengan test Anti Sars CoV-2 di Laboratorium Klinik Populer. Tenang aja, harga terjangkau dan Ada promo Khusus Harga Cuma 200 ribu dan Anda juga bisa mengetahui kondisi kesehatanmu secara berkala dengan pemeriksaan penunjang lainnya. PROMO INI JUGA BISA KAMU NIKMATI DI SEMUA CABANG LABORATORIUM KAMI DI. Jl. Di Prodia ada Anti SARS-CoV-2-Kuantitatif, untuk cek titer antibodi seseorang yang ada di tubuh. DIsarankannya untuk yang sudah vaksin atau penyintas vaksin, dan yang ingin mendonor plasma konvalesen," tambahnya. Namun yang pasti Dinar menjelaskan bahwa Prodia akan memberi catatan pada hasil tes serologi baik mau yang non reaktif atau reaktif. ^{NationalCenter for Biotechnology Information} .

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