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1.
Klin Lab Diagn ; 65(11): 688-692, 2020 Dec 04.
Article in English | MEDLINE | ID: covidwho-1780383

ABSTRACT

The study presents the results of the creation and evaluation of the diagnostic characteristics of the rapid immunochromatographic test for the qualitative detection and differentiation of IgM/IgG antibodies to SARS-CoV-2 in human serum, plasma, and whole blood "ИХА-COVID-19-IgM / IgG". Have been tested some samples without antibodies to SARS-CoV-2 and a samples with two and one type of specific antibodies. The coincidence of the results of immunochromatographic analysis with the results of the immunochemiluminescent method was 87.2%. Test kit can be use as the rapid diagnostic test in the context of the COVID-19 pandemic and to assess the immune status of convalescents.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing , COVID-19/diagnosis , Immunoassay , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Humans
2.
Klin Lab Diagn ; 65(11): 683-687, 2020 Dec 04.
Article in English | MEDLINE | ID: covidwho-1780382

ABSTRACT

A new original Russian test kit for the detection of IgG-antibodies to the causative agent of COVID-19 - coronavirus SARS-CoV-2 by the method of enzyme-linked immunosorbent assay (ELISA) on a solid-phase «ELISA-SARS-CoV-2-AT-G¼ has been developed. In comparative tests with similar test systems «Vitrotest® SARS-CoV-2 IgG¼ (Vitrotest, Ukraine) and «Anti-SARS-Cov-2 ELISA (IgG)¼ (EUROIMMUN AG, Germany) high diagnostic efficiency of the new test system was shown.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Immunoglobulin G/analysis , Clinical Laboratory Techniques , Humans , Plasma , Reagent Kits, Diagnostic
3.
Klin Lab Diagn ; 66(4): 210-212, 2021 Apr 17.
Article in English | MEDLINE | ID: covidwho-1780502

ABSTRACT

To study the diagnostic characteristics of test systems for detecting antibodies to SARS-Cov-2. We studied the diagnostic characteristics of two test systems for detecting antibodies to SARS-Cov-2, registered in the Russian Federation. The first test system is a kit for detecting total antibodies to SARS-Cov-2 using immunochemiluminescence analysis on the «Cobas e 411¼ analyzer («Roche Diagnostics¼, Germany). The second test system is a kit for detecting IgM and IgG to SARS-Cov-2 («Core Technology Co., Ltd¼, China) by immunochromatographic analysis. The biological material for the study was blood serum. We assessed: diagnostic sensitivity, diagnostic specificity, and predictive value of positive and negative results. In the test system for detecting total antibodies to SARS-CoV-2, using an IHLA, the diagnostic sensitivity and specificity were 100%; the predictive value of positive and negative results was 100%. In the test system for the detection of IgM and IgG to Sars-CoV-2, using IHA, diagnostic sensitivity for IgM and IgG were 100%; diagnostic specificity for IgM - 60%, for IgG - 72%; predictive value of a positive result for IgM - 60%, IgG - 68,18%; predictive value of negative results for IgM and IgG - 100%. The best diagnostic characteristics were found in the test system for the detection of total antibodies to SARS-Cov-2, which must be taken into account when deciding whether to purchase test systems for the detection of antibodies to SARS-Cov-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Humans , Immunoglobulin G , Immunoglobulin M , Russia , Sensitivity and Specificity , Serologic Tests
4.
J Matern Fetal Neonatal Med ; 35(8): 1610-1618, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1747012

ABSTRACT

Corona virus disease 2019 started in December 2019 as an outbreak of unexplained pneumonias in Wuhan, a city in Hubei province of China. This illness emerged as an epidemic in China and later spread to almost all countries over the globe except Antarctica. This is caused by a beta Corona virus, which is genetically similar to SARS virus. The predominant mode of transmission is via droplet spread, when the infected person coughs, sneezes or talks the virus is released in the respiratory secretions. As there are only a few cases of COVID 19 in neonates, there is no convincing evidence to support the possibility of vertical transmission. Clinical presentation in neonates is nonspecific, commonly observed are temperature instability, respiratory distress, poor feeding, lethargy, vomiting and diarrhea. Laboratory examinations may be nonspecific. Definitive test for 2019-nCoV is the detection of viral nucleic acid by real-time fluorescence polymerase chain reaction (RT-PCR). Suspected and confirmed COVID positive mothers should be delivered in separate delivery rooms and operation theaters. Since there is no approved treatment or drug for this disease, prevention of infection and breaking the chain of transmission plays a crucial role.


Subject(s)
COVID-19 , SARS Virus , COVID-19/diagnosis , Disease Outbreaks , Humans , Infant, Newborn , Infectious Disease Transmission, Vertical , SARS-CoV-2
5.
Int J Mol Sci ; 21(8)2020 Apr 18.
Article in English | MEDLINE | ID: covidwho-1725799

ABSTRACT

COVID-19 has become a major global public health burden, currently causing a rapidly growing number of infections and significant morbidity and mortality around the world. Early detection with fast and sensitive assays and timely intervention are crucial for interrupting the spread of the COVID-19 virus (SARS-CoV-2). Using a mismatch-tolerant amplification technique, we developed a simple, rapid, sensitive and visual reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for SARS-CoV-2 detection based on its N gene. The assay has a high specificity and sensitivity, and robust reproducibility, and its results can be monitored using a real-time PCR machine or visualized via colorimetric change from red to yellow. The limit of detection (LOD) of the assay is 118.6 copies of SARS-CoV-2 RNA per 25 µL reaction. The reaction can be completed within 30 min for real-time fluorescence monitoring, or 40 min for visual detection when the template input is more than 200 copies per 25 µL reaction. To evaluate the viability of the assay, a comparison between the RT-LAMP and a commercial RT-qPCR assay was made using 56 clinical samples. The SARS-CoV-2 RT-LAMP assay showed perfect agreement in detection with the RT-qPCR assay. The newly-developed SARS-CoV-2 RT-LAMP assay is a simple and rapid method for COVID-19 surveillance.


Subject(s)
Betacoronavirus/isolation & purification , Clinical Laboratory Techniques/methods , Coronavirus Infections , Pandemics , Pneumonia, Viral , Betacoronavirus/genetics , Biological Assay , COVID-19 , COVID-19 Testing , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Humans , Nucleic Acid Amplification Techniques , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Reverse Transcriptase Polymerase Chain Reaction , Reverse Transcription , SARS-CoV-2 , Sensitivity and Specificity
6.
Results Chem ; 3: 100138, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-1596100

ABSTRACT

Developing robust methods to detect the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a causative agent for the current global health pandemic, is an exciting area of research. Nevertheless, the currently used conventional reverse transcription-polymerase chain reaction (RT-PCR) technique in COVID-19 detection endures with some inevitable limitations. Consequently, the establishment of rapid diagnostic tools and quick isolation of infected patients is highly essential. Furthermore, the requirement of point-of-care testing is the need of the hour. Considering this, we have provided a brief review of the use of very recently reported robust spectral tools for rapid COVID-19 detection. The spectral tools include, colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), with the admittance of principal component analysis (PCA) and machine learning (ML) for meeting the high-throughput and fool-proof platforms for the detection of SARS-CoV-2, are reviewed. Recently, these techniques have been readily applied to screen a large number of suspected patients within a short period and they demonstrated higher sensitivity for the detection of COVID-19 patients from unaffected human subjects.

7.
Biomicrofluidics ; 14(6): 061507, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-1574498

ABSTRACT

In December 2019, coronavirus disease 2019 became a pandemic affecting more than 200 countries and territories. Millions of lives are still affected because of mandatory quarantines, which hamstring economies and induce panic. Immunology plays a major role in the modern field of medicine, especially against virulent infectious diseases. In this field, neutralizing antibodies are heavily studied because they reflect the level of infection and individuals' immune status, which are essential when considering resumption of work, flight travel, and border entry control. More importantly, it also allows evaluating the antiviral vaccine efficacy as vaccines are still known for being the ultimate intervention method to inhibit the rapid spread of virulent infectious diseases. In this Review, we first introduce the host immune response after the infection of SARS-CoV-2 and discuss the latest results using conventional immunoassays. Next, as an enabling platform for detection with sufficient sensitivity while saving analysis time and sample size, the progress of microfluidic-based immunoassays is discussed and compared based on surface modification, microfluidic kinetics, signal output, signal amplification, sample matrix, and the detection of anti-SARS-CoV-2 antibodies. Based on the overall comparison, this Review concludes by proposing the future integration of visual quantitative signals on microfluidic devices as a more suitable approach for general use and large-scale surveillance.

8.
Infect Control Hosp Epidemiol ; 42(11): 1340-1344, 2021 11.
Article in English | MEDLINE | ID: covidwho-1574695

ABSTRACT

BACKGROUND: Widespread testing for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) is necessary to curb the spread of coronavirus disease 2019 (COVID-19), but testing is undermined when the only option is a nasopharyngeal swab. Self-collected swab techniques can overcome many of the disadvantages of a nasopharyngeal swab, but they require evaluation. METHODS: Three self-collected non-nasopharyngeal swab techniques (saline gargle, oral swab and combined oral-anterior nasal swab) were compared to a nasopharyngeal swab for SARS-CoV-2 detection at multiple COVID-19 assessment centers in Toronto, Canada. The performance characteristics of each test were assessed. RESULTS: The adjusted sensitivity of the saline gargle was 0.90 (95% CI 0.86-0.94), the oral swab was 0.82 (95% CI, 0.72-0.89) and the combined oral-anterior nasal swab was 0.87 (95% CI, 0.77-0.93) compared to a nasopharyngeal swab, which demonstrated a sensitivity of ˜90% when all positive tests were the reference standard. The median cycle threshold values for the SARS-CoV-2 E-gene for concordant and discordant saline gargle specimens were 17 and 31 (P < .001), for the oral swabs these values were 17 and 28 (P < .001), and for oral-anterior nasal swabs these values were 18 and 31 (P = .007). CONCLUSIONS: Self-collected saline gargle and an oral-anterior nasal swab have a similar sensitivity to a nasopharyngeal swab for the detection of SARS-CoV-2. These alternative collection techniques are cheap and can eliminate barriers to testing, particularly in underserved populations.


Subject(s)
COVID-19 , Outpatients , Humans , Nasopharynx , SARS-CoV-2 , Saliva , Specimen Handling
9.
Clin Chem Lab Med ; 59(8): 1463-1467, 2021 07 27.
Article in English | MEDLINE | ID: covidwho-1546996

ABSTRACT

OBJECTIVES: COVID-19 has brought about tests from many manufacturers. While molecular and rapid antigen tests are targeted for early diagnosis, immunoassays have a larger role in epidemiological studies, understanding longitudinal immunity, and in vaccine development and response. METHODS: The performance of the LIAISON® SARS-CoV-2 TrimericS IgG assay was evaluated against the Beckman ACCESS SARS-CoV-2 IgG assay in New Mexico, and against the Siemens ADVIA Centaur COV2G assay in New York. Discordant samples were parsed using a microneutralization assay. RESULTS: A SARS-CoV-2 antibody positivity rate of 23.8% was observed in the samples tested in New York (September 2020), while in the same month the positivity rate was 1.5% in New Mexico. Positive and negative agreement were 67.6% (95% CI 49.5-82.6%) and 99.8% (95% CI 99.5-99.9%), respectively, with the Beckman test, and 98.0% (95% CI 95.7-99.3%) and 94.8% (95% CI 93.4-96.0%), respectively, with the Siemens test. Receiver operating characteristic analysis for the detection of SARS-CoV-2 antibodies discloses an AUC, area under the curve, of 0.996 (95% CI 0.992-0.999) for the LIAISON® SARS-CoV-2 TrimericS IgG assay. The criterion associated to the Youden Index was determined to be >12.9 kAU/L with a sensitivity of 99.44% and a specificity of 99.82%. CONCLUSIONS: The LIAISON® SARS-CoV-2 TrimericS IgG assay is highly sensitive and specific. The balance of these parameters, without emphasis on high specificity alone, is particularly important when applied to high prevalence populations, where a highly sensitive assay will result in reporting a lower number of false negative subjects.


Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , Immunoassay/methods , Immunoglobulin G/blood , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/immunology , Area Under Curve , Automation , COVID-19/virology , Humans , ROC Curve , Reagent Kits, Diagnostic , SARS-CoV-2/isolation & purification , Sensitivity and Specificity
10.
Clin Infect Dis ; 73(9): e3130-e3132, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1532491

ABSTRACT

We investigated feasibility and accuracy of an interferon-γ release assay (IGRA) for detection of T-cell responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Whole blood IGRA accurately distinguished between convalescent and uninfected healthy blood donors with a predominantly CD4+ T-cell response. SARS-CoV-2 IGRA may serve as a useful diagnostic tool in managing the coronavirus disease 2019 pandemic.


Subject(s)
COVID-19 , Interferon-gamma Release Tests , Antibodies, Viral , Humans , SARS-CoV-2 , T-Lymphocytes
11.
J Endocrinol Invest ; 44(12): 2675-2684, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1504521

ABSTRACT

PURPOSE: Due to relevant repercussions on reproductive medicine, we aimed to evaluate feasibility of RT-PCR as a detection method of SARS-CoV-2 RNA in seminal fluid. METHODS: A qualitative determination of the RT-PCR assays in semen was performed through different approaches: (1) efficiency of RNA extraction from sperm and seminal plasma was determined using PRM1 and PRM2 mRNA and a heterologous system as control; (2) samples obtained by diluting viral preparation from a SARS-CoV-2 panel (virus cultured in Vero E6 cell lines) were tested; (3) viral presence in different fractions of seminal fluid (whole sample, seminal plasma and post-centrifugation pellet) was evaluated. Semen samples from mild and recovered COVID-19 subjects were collected by patients referring to the Infectious Disease Department of the Policlinico Umberto I Hospital - "Sapienza" University of Rome. Control subjects were recruited at the Laboratory of Seminology-Sperm Bank "Loredana Gandini'' of the same hospital. RESULTS: The control panel using viral preparations diluted in saline and seminal fluid showed the capability to detect viral RNA presence with Ct values depending on the initial viral concentration. All tested semen samples were negative for SARS-CoV-2, regardless of the nasopharyngeal swab result or seminal fluid fraction. CONCLUSION: These preliminary data show that RT-PCR for SARS-CoV-2 RNA testing appears to be a feasible method for the molecular diagnosis of SARS-CoV-2 in seminal fluid, supported by results of the control panel. The ability to detect SARS-CoV-2 in semen is extremely important for reproductive medicine, especially in assisted reproductive technology and sperm cryopreservation.


Subject(s)
COVID-19/diagnosis , Pathology, Molecular/methods , Semen/virology , Adult , Animals , Chlorocebus aethiops , Feasibility Studies , Humans , Male , RNA, Messenger/chemistry , RNA, Viral/chemistry , Real-Time Polymerase Chain Reaction , Reproductive Techniques , Vero Cells
12.
Wellcome Open Res ; 6: 9, 2021.
Article in English | MEDLINE | ID: covidwho-1502788

ABSTRACT

The ongoing pandemic of SARS-CoV-2 calls for rapid and cost-effective methods to accurately identify infected individuals. The vast majority of patient samples is assessed for viral RNA presence by RT-qPCR. Our biomedical research institute, in collaboration between partner hospitals and an accredited clinical diagnostic laboratory, established a diagnostic testing pipeline that has reported on more than 252,000 RT-qPCR results since its commencement at the beginning of April 2020. However, due to ongoing demand and competition for critical resources, alternative testing strategies were sought. In this work, we present a clinically-validated procedure for high-throughput SARS-CoV-2 detection by RT-LAMP in 25 minutes that is robust, reliable, repeatable, sensitive, specific, and inexpensive.

13.
Clin Infect Dis ; 73(9): e2952-e2959, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1501018

ABSTRACT

BACKGROUND: The detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA by reverse-transcription polymerase chain reaction (PCR) does not necessarily indicate shedding of infective virions. There are limited data on the correlation between the isolation of SARS-CoV-2, which likely indicates infectivity, and PCR. METHODS: A total of 195 patients with Coronavirus disease 2019 were tested (outpatients, n = 178; inpatients, n = 12; and critically unwell patients admitted to the intensive care unit [ICU] patients, n = 5). SARS-CoV-2 PCR-positive samples were cultured in Vero C1008 cells and inspected daily for cytopathic effect (CPE). SARS-CoV-2-induced CPE was confirmed by PCR of culture supernatant. Where no CPE was observed, PCR was performed on day 4 to confirm absence of virus replication. The cycle thresholds (Cts) of the day 4 PCR (Ctculture) and the PCR of the original clinical sample (Ctsample) were compared, and positive cultures were defined where Ctsample - Ctculture was ≥3. RESULTS: Of 234 samples collected, 228 (97%) were from the upper respiratory tract. SARS-CoV-2 was isolated from 56 (24%), including in 28 of 181 (15%), 19 of 42 (45%), and 9 of 11 samples (82%) collected from outpatients, inpatients, and ICU patients, respectively. All 56 samples had Ctsample ≤32; CPE was observed in 46 (20%). The mean duration from symptom onset to culture positivity was 4.5 days (range, 0-18). SARS-CoV-2 was significantly more likely to be isolated from samples collected from inpatients (P < .001) and ICU patients (P < .0001) compared with outpatients, and in samples with lower Ctsample. CONCLUSIONS: SARS-CoV-2 culture may be used as a surrogate marker for infectivity and inform de-isolation protocols.


Subject(s)
COVID-19 , Animals , Chlorocebus aethiops , Critical Care , Humans , Immunologic Tests , SARS-CoV-2 , Vero Cells
14.
Influenza Other Respir Viruses ; 15(3): 381-388, 2021 05.
Article in English | MEDLINE | ID: covidwho-1452868

ABSTRACT

BACKGROUND: Reliable diagnostics are a key to identifying influenza infections. OBJECTIVES: Our objectives were to describe the detection of influenza among severe acute respiratory infection (SARI) cases, to compare test results from the Fast Track Diagnostics (FTD) Kit for influenza detection to the Centers for Disease Control (CDC) human influenza virus detection and characterization panel, and to assess seasonality of influenza in Burkina Faso. METHODS: Nasopharyngeal and oropharyngeal specimens from SARI cases (hospitalized patients with fever, cough, and onset in the previous 10 days) were tested using the FTD-33 Kit and the CDC rRT-PCR influenza assays. We assessed sensitivity and specificity of the FTD-33 Kit for detecting influenza A, influenza B, and the influenza A(H1N1)pdm09 strain using the CDC human influenza rRT-PCR panel as the gold standard. RESULTS: From December 2016 to February 2019, 1706 SARI cases were identified, 1511 specimens were tested, and 211 were positive for influenza A (14.0%) and 100 for influenza B (6.6%) by either assay. Higher influenza circulation occurred between November and April with varying peaks of influenza A and influenza B. Sensitivity of the FTD-33 assay was 91.9% for influenza A, 95.7% for influenza B, and 93.8% for A(H1N1)pdm09 subtype. Specificity was over 99% for all three tests. CONCLUSIONS: Our study indicates that Burkina Faso has one peak of influenza each year which is similar to the Northern Hemisphere and differs from other countries in West Africa. We found high concordance of influenza results between the two assays indicating FTD-33 can be used to reliably detect influenza among SARI cases.


Subject(s)
Influenza A Virus, H1N1 Subtype , Influenza, Human , Centers for Disease Control and Prevention, U.S. , Humans , Influenza A Virus, H1N1 Subtype/genetics , Influenza, Human/diagnosis , Influenza, Human/epidemiology , Laboratories , Reverse Transcriptase Polymerase Chain Reaction , United States
16.
IEEE Trans Biomed Circuits Syst ; 15(4): 666-678, 2021 08.
Article in English | MEDLINE | ID: covidwho-1412308

ABSTRACT

For precise health status monitoring and accurate disease diagnostics in the current COVID-19 pandemic, it is essential to detect various kinds of target signals robustly under high noise and strong interferences. Moreover, the health monitoring system is preferred to be realized in a small form factor for convenient mass deployments. A CMOS-integrated coherent sensing platform is proposed to achieve the goal, which synergetically leverages quadrature coherent photoacoustic (PA) detection and coherent radar sensing for achieving universal healthcare. By utilizing configurable mixed-signal quadrature coherent PA detection, high sensitivity and enhanced specificity can be achieved. In-phase (I) and quadrature (Q) templates are specifically designed to accurately sense and precisely reconstruct the target PA signals in a coherent mode. By mixed-signal implementation leveraging an FPGA to generate template waveforms adaptively, accurate tracking and precise reconstruction on the target PA signal can be attained based on the early-late tracking principle. The multiplication between the received PA signal and the templates is implemented efficiently in analog-domain by the Gilbert cell on-chip. In vivo blood temperature monitoring was realized based on the integrated PA sensing platform fabricated in a 65-nm CMOS process. With an integrated radar sensor deployed in the indoor scenario, noncontact monitoring on respiration and heartbeat rates can be attained based on electromagnetic (EM) sensing. By complementary usage of PA-EM sensing mechanisms, comprehensive health status monitoring and precise remote disease diagnostics can be achieved for the currentglobal COVID-19 pandemic and the future pervasive healthcare in the Internet of Everything (IoE) era.


Subject(s)
Body Temperature , COVID-19 , Radar , Signal Processing, Computer-Assisted , Vital Signs , Humans , Pandemics
17.
IEEE J Biomed Health Inform ; 25(9): 3332-3339, 2021 09.
Article in English | MEDLINE | ID: covidwho-1406537

ABSTRACT

With the popularization of computer-aided diagnosis (CAD) technologies, more and more deep learning methods are developed to facilitate the detection of ophthalmic diseases. In this article, the deep learning-based detections for some common eye diseases, including cataract, glaucoma, and age-related macular degeneration (AMD), are analyzed. Generally speaking, morphological change in retina reveals the presence of eye disease. Then, while using some existing deep learning methods to achieve this analysis task, the satisfactory performance may not be given, since fundus images usually suffer from the impact of data imbalance and outliers. It is, therefore, expected that with the exploration of effective and robust deep learning algorithms, the detection performance could be further improved. Here, we propose a deep learning model combined with a novel mixture loss function to automatically detect eye diseases, through the analysis of retinal fundus color images. Specifically, given the good generalization and robustness of focal loss and correntropy-induced loss functions in addressing complex dataset with class imbalance and outliers, we present a mixture of those two losses in deep neural network model to improve the recognition performance of classifier for biomedical data. The proposed model is evaluated on a real-life ophthalmic dataset. Meanwhile, the performance of deep learning model with our proposed loss function is compared with the baseline models, while adopting accuracy, sensitivity, specificity, Kappa, and area under the receiver operating characteristic curve (AUC) as the evaluation metrics. The experimental results verify the effectiveness and robustness of the proposed algorithm.


Subject(s)
Deep Learning , Glaucoma , Algorithms , Fundus Oculi , Glaucoma/diagnostic imaging , Humans , Neural Networks, Computer , ROC Curve
20.
PLoS One ; 16(5): e0252621, 2021.
Article in English | MEDLINE | ID: covidwho-1388920

ABSTRACT

BACKGROUND: Dried blood spots (DBS) are an established specimen type for clinical testing given their low cost, ease of collection and storage, and convenient shipping capabilities through the postal system. These attributes are complementary to the expansion of SARS-CoV-2 serologic testing, which may be used to inform community seroprevalence rates. METHODS: The Luminex xMAP SARS-CoV-2 Multi-Antigen assay utilizes magnetic beads labeled with three viral antigens (nucleocapsid [NC], receptor binding domain [RBD], spike S1 subunit) to detect anti-viral IgG-class antibodies, and has Food and Drug Administration (FDA) Emergency Use Authorization (EUA) for use in serum and plasma. This assay was modified for use with DBS and validated against paired sera tested by one of two reference assays: the Roche Diagnostics Elecsys anti-SARS-CoV-2 ECLIA or the Euroimmun anti-SARS-CoV-2 IgG ELISA. RESULTS: 159 paired DBS and serum specimens analyzed using the modified Luminex xMAP assay on DBS and the reference methods on serum showed an overall concordance of 96.9% (154/159). Use of multivariate pattern recognition software (CLIR) for post-analytical interpretation of the Luminex xMAP DBS assay results, instead of manufacturer provided interpretive thresholds, increased overall qualitative result concordance to 99.4% (158/159) between the modified Luminex xMAP DBS and reference results. CONCLUSIONS: Use of DBS for detection of antibodies against SARS-CoV-2 provides comparable results to those obtained using serum. DBS concordance was improved with multivariate pattern recognition software (CLIR). We demonstrate that DBS are a reliable specimen type for SARS-CoV-2 antibody detection using the modified Luminex xMAP assay.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19/blood , Dried Blood Spot Testing , Immunoglobulin G/blood , SARS-CoV-2 , Adult , Aged , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged
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