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1.
Clin Infect Dis ; 71(15): 778-785, 2020 07 28.
Article in English | MEDLINE | ID: covidwho-1217823

ABSTRACT

BACKGROUND: The emergence of coronavirus disease 2019 (COVID-19) is a major healthcare threat. The current method of detection involves a quantitative polymerase chain reaction (qPCR)-based technique, which identifies the viral nucleic acids when present in sufficient quantity. False-negative results can be achieved and failure to quarantine the infected patient would be a major setback in containing the viral transmission. We aim to describe the time kinetics of various antibodies produced against the 2019 novel coronavirus (SARS-CoV-2) and evaluate the potential of antibody testing to diagnose COVID-19. METHODS: The host humoral response against SARS-CoV-2, including IgA, IgM, and IgG response, was examined by using an ELISA-based assay on the recombinant viral nucleocapsid protein. 208 plasma samples were collected from 82 confirmed and 58 probable cases (qPCR negative but with typical manifestation). The diagnostic value of IgM was evaluated in this cohort. RESULTS: The median duration of IgM and IgA antibody detection was 5 (IQR, 3-6) days, while IgG was detected 14 (IQR, 10-18) days after symptom onset, with a positive rate of 85.4%, 92.7%, and 77.9%, respectively. In confirmed and probable cases, the positive rates of IgM antibodies were 75.6% and 93.1%, respectively. The detection efficiency by IgM ELISA is higher than that of qPCR after 5.5 days of symptom onset. The positive detection rate is significantly increased (98.6%) when combining IgM ELISA assay with PCR for each patient compared with a single qPCR test (51.9%). CONCLUSIONS: The humoral response to SARS-CoV-2 can aid in the diagnosis of COVID-19, including subclinical cases.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Immunity, Humoral/immunology , Pneumonia, Viral/diagnosis , Pneumonia, Viral/immunology , Adult , Amino Acid Sequence , Antibodies, Viral/immunology , COVID-19 , Child , Child, Preschool , Coronavirus Infections/virology , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , Polymerase Chain Reaction/methods , SARS-CoV-2
2.
Front Public Health ; 8: 620222, 2020.
Article in English | MEDLINE | ID: covidwho-1121963

ABSTRACT

Introduction: Few data on the diagnostic performance of serological tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are currently available. We evaluated sensitivity and specificity of five different widely used commercial serological assays for the detection of SARS-CoV-2-specific IgG, IgM, and IgA antibodies using reverse transcriptase-PCR assay in nasopharyngeal swab as reference standard test. Methods: A total of 337 plasma samples collected in the period April-June 2020 from SARS-CoV-2 RT-PCR positive (n = 207) and negative (n = 130) subjects were investigated by one point-of-care lateral flow immunochromatographic assay (LFIA IgG and IgM, Technogenetics) and four fully automated assays: two chemiluminescence immunoassays (CLIA-iFlash IgG and IgM, Shenzhen YHLO Biotech and CLIA-LIAISON® XL IgG, DiaSorin), one electrochemiluminescence immunoassay (ECLIA-Elecsys® total predominant IgG, Roche), and one enzyme-linked immunosorbent assay (ELISA IgA, Euroimmune). Results: The overall sensitivity of all IgG serological assays was >80% and the specificity was >97%. The sensitivity of IgG assays was lower within 2 weeks from the onset of symptoms ranging from 70.8 to 80%. The LFIA and CLIA-iFlash IgM showed an overall low sensitivity of 47.6 and 54.6%, while the specificity was 98.5 and 96.2%, respectively. The ELISA IgA yielded a sensitivity of 84.3% and specificity of 81.7%. However, the ELISA IgA result was indeterminate in 11.7% of cases. Conclusions: IgG serological assays seem to be a reliable tool for the retrospective diagnosis of SARS-CoV-2 infection. IgM assays seem to have a low sensitivity and IgA assay is limited by a substantial rate of indeterminate results.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19/diagnosis , SARS-CoV-2/immunology , COVID-19/blood , COVID-19/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , ROC Curve , SARS-CoV-2/isolation & purification , Sensitivity and Specificity
3.
Pathology ; 52(7): 764-769, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-1041681

ABSTRACT

Many unanswered questions remain regarding the role of SARS-CoV-2 serological assays in this unfolding COVID-19 pandemic. These include their utility for the diagnosis of acute SARS-CoV-2 infection, past infection or exposure, correlation with immunity and the effective duration of immunity. This study examined the performance of three laboratory based serological assays, EUROIMMUN Anti-SARS-CoV-2 IgA/IgG, MAGLUMI 2000 Plus 2019-nCov IgM/IgG and EDI Novel Coronavirus (COVID-19) IgM/IgG immunoassays. We evaluated 138 samples from a reference non-infected population and 71 samples from a cohort of 37 patients with SARS-CoV-2 confirmed positive by RT-PCR. The samples were collected at various intervals of 0-45 days post symptoms onset (PSO). Specificity and sensitivity of these assays was 60.9%/71.4% (IgA) and 94.2%/63.3% (IgG) for EUROIMMUN; 98.5%/18.4% (IgM) and 97.8%/53.1% (IgG) for MAGLUMI; and 94.9%/22.5% (IgM) and 93.5%/57.1% (IgG) for EDI, respectively. When samples collected ≥14 days PSO were considered, the sensitivities were 100.0 and 100.0%; 31.0 and 82.8%; 34.5 and 57.1%, respectively. Using estimated population prevalence of 0.1, 1, and 10%, the positive predictive value of all assays remained low. The EUROIMMUN Anti-SARS-CoV-2 IgA lacked specificity for acute diagnosis and all IgM assays offered poor diagnostic utility. Seroconversion can be delayed although all patients had seroconverted at 28 days in our cohort with the EUROIMMUN Anti-SARS-CoV-2 IgG. Despite this, with specificity of only 94% this assay would not be satisfactory for seroprevalence studies in the general Australian population given this is likely to be currently <1%.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Australia , COVID-19/blood , Cohort Studies , Humans , SARS-CoV-2 , Sensitivity and Specificity
4.
J Clin Virol ; 133: 104663, 2020 12.
Article in English | MEDLINE | ID: covidwho-1014606

ABSTRACT

BACKGROUND: Antibody testing has recently emerged as an option to assist with determining exposure to SARS-CoV-2, the causative agent of COVID-19. Elucidation of the kinetics and duration of the humoral response is important for clinical management and interpreting results from serological surveys. OBJECTIVES: Here we evaluated the clinical performance of Abbott SARS-CoV-2 IgM and IgG assays, as well as the longitudinal dynamics of the antibody response in symptomatic COVID-19 patients. STUDY DESIGN AND RESULTS: The diagnostic specificity was 100 % for IgM and 99.67 % for IgG using 300 pre-COVID-19 serum specimens. Using 1349 sequential serum samples collected up to 168 days post symptom onset from 427 PCR-confirmed individuals, clinical test sensitivity of the SARS-CoV-2 IgM assay was 24.6 % at ≤7 days, 75.3 % at 8-14 days, 95.0 % at 15-21 days, and 96.0 % at 4-5 weeks (peak test sensitivity). The median duration of time for IgM seroconversion was 10 days. IgM levels declined steadily 4-5 weeks after symptom onset, and the positive rate dropped to 30.8 % at >3 months. The diagnostic sensitivity for the SARS-CoV-2 IgG assay post symptom onset was 23.2 % at ≤7 days, 69.5 % at 8-14 days, 93.6 % at 15-21 days, and 99.6 % at 4-5 weeks (peak test sensitivity). The median duration of time for IgG seroconversion was 11.5 days. During the convalescent phase of the infection, a decline in the IgG level was observed in patients who were followed for >100 days. Despite that decline, 92.3 % of the patient cohort remained IgG positive 3-6 months following symptom onset. CONCLUSIONS: This study demonstrates the Abbott IgM assay against SARS-CoV-2 is detected slightly earlier compared to IgG, with both tests exhibiting excellent overall sensitivity and specificity. In symptomatic patients who test negative by PCR for a SARS-CoV-2 infection, assessing IgM and IgG antibodies can aid in supporting a diagnosis of COVID-19.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19/diagnosis , Immunity, Humoral , Immunoglobulin G/blood , Immunoglobulin M/blood , COVID-19/immunology , Cohort Studies , Humans , Longitudinal Studies , Reproducibility of Results , Sensitivity and Specificity
5.
J Clin Microbiol ; 59(1)2020 12 17.
Article in English | MEDLINE | ID: covidwho-991747

ABSTRACT

Critical evaluation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic assays is needed to guide clinical decision-making and ensure that these assays provide optimal benefit to patients and the public. Here, three commercially available assays with widespread distribution capabilities are compared. A total of 667 specimens, 103 from patients with confirmed SARS-CoV-2 infections and 564 collected prior to the emergence of SARS-CoV-2, were analyzed in parallel using the Roche Elecsys SARS-CoV-2 total antibody and Abbott Alinity SARS-CoV-2 IgG assays; a subset of 55 samples from patients with confirmed SARS-CoV-2 infections was additionally evaluated using the Abbott Architect SARS-CoV-2 IgM assay. Qualitative agreement between the Abbott IgG and Roche total antibody assays was 98.7% (658/667), with Cohen's kappa value of 0.919 (95% confidence interval [CI], 0.867 to 0.972). Qualitative agreements with the Abbott IgM assay were 92.7% (51/55, Abbott IgG) and 85.5% (47/55, Roche total antibody). Diagnostic specificities determined using pre-COVID-19 samples for the Abbott IgG and Roche total antibody assays were 99.65% (95% CI, 98.72 to 99.90%) and 100.00% (95% CI, 99.32 to 100.00%), respectively, spanning claims made by each manufacturer. Diagnostic sensitivities increased for all three assays with increasing time since the onset of symptoms. Among 51 patients with confirmed SARS-CoV-2 infections, 23 (45.1%), 24 (47.1%), and 22 (43.1%) were reactive by the Abbott IgG, Roche total antibody, and Abbott IgM assays, respectively, with sampling times 0 to 56 days post-positive PCR (median/mean, 2/6.2 days). Combining IgG and IgM screening identified 4/55 additional samples with detectable antibodies that would not have been observed using the assays independently. Notably, one immunocompromised patient with confirmed SARS-CoV-2 infection showed no detectable antibodies using any of the three assays 43 days after onset of symptoms.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoglobulin G/blood , Immunoglobulin M/blood , Humans , SARS-CoV-2/immunology , Sensitivity and Specificity
7.
Clin Chem Lab Med ; 58(7): 1081-1088, 2020 06 25.
Article in English | MEDLINE | ID: covidwho-937249

ABSTRACT

Background Coronavirus disease 2019, abbreviated to COVID-19, represents an emerging health threat worldwide as, after initial reports in China, it has continued to spread rapidly. The clinical spectrum of the disease varies from mild to severe acute respiratory distress syndrome (ARDS). Moreover, many patients can be asymptomatic, thus increasing the uncertainty of the diagnostic work-up. Laboratory tests play a pivotal role in the diagnosis and management of COVID-19, the current gold standard being real-time reverse transcription polymerase chain reaction (rRT-PCR) on respiratory tract specimens. However, the diagnostic accuracy of rRT-PCR depends on many pre-analytical and analytical variables. The measurement of specific COVID-19 antibodies (both IgG and IgM) should serve as an additional, non-invasive tool for disease detection and management. Methods The imprecision of the MAGLUMI™ 2000 Plus 2019-nCov IgM and IgG assays (Snibe, Shenzhen, China) was assessed by adopting the Clinical and Laboratory Standards Institute (CLSI) EP15-A3 protocol. Linearity of dilution and recovery was evaluated by means of mixes of high-level pools and low-level pools of serum samples. Immunoglobulin time kinetics were evaluated using a series of serum samples, repeatedly collected from COVID-19-positive patients at different times, from <5 days up to 26-30 days. Results Findings at the analytical validation of the assay carried out according to the CLSI EP15-A3 guideline demonstrated that imprecision and repeatability were acceptable (repeatability was <4% and <6% for IgM and IgG, respectively, whilst intermediate imprecision was <6%). In addition, results of dilution and recovery studies were satisfactory. The kinetics of COVID-19 antibodies confirmed previously reported findings, showing a rapid increase of both IgM and IgG after 6-7 days from the symptom onset. IgG had 100% sensitivity on day 12, whilst 88% was the higher positive rate achieved for IgM after the same time interval. Conclusions The findings of this study demonstrate the validity of the MAGLUMI 2000 Plus CLIA assay for the measurement of specific IgM and IgG in sera of COVID-19 patients, and for obtaining valuable data on the kinetics of both (IgM and IgG) COVID-19 antibodies. These data represent a pre-requisite for the appropriate utilization of specific antibodies for the diagnosis and management of COVID-19 patients.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/immunology , Immunoenzyme Techniques/methods , Pneumonia, Viral/immunology , Antibodies, Viral/blood , COVID-19 , China , Clinical Laboratory Techniques/methods , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin M/blood , Immunoglobulin M/immunology , Kinetics , Luminescent Measurements/methods , Pandemics , Real-Time Polymerase Chain Reaction , SARS-CoV-2
8.
Biomed Res Int ; 2020: 9878453, 2020.
Article in English | MEDLINE | ID: covidwho-934159

ABSTRACT

Knowledge of the sensitivities of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody tests beyond 35 days after the clinical onset of COVID-19 is insufficient. We aimed to describe positivity rate of SARS-CoV-2 assays employing three different measurement principles over a prolonged period. Two hundred sixty-eight samples from 180 symptomatic patients with COVID-19 and a reverse transcription polymerase chain reaction (RT-PCR) test followed by serological investigation of SARS-CoV-2 antibodies were included. We conducted three chemiluminescence (including electrochemiluminescence assay (ECLIA)), four enzyme-linked immunosorbent assay (ELISA), and one lateral flow immunoassay (LFIA) test formats. Positivity rates, as well as positive (PPVs) and negative predictive values (NPVs), were calculated for each week after the first clinical presentation for COVID-19. Furthermore, combinations of tests were assessed within an orthogonal testing approach employing two independent assays and predictive values were calculated. Heat maps were constructed to graphically illustrate operational test characteristics. During a follow-up period of more than 9 weeks, chemiluminescence assays and one ELISA IgG test showed stable positivity rates after the third week. With the exception of ECLIA, the PPVs of the other chemiluminescence assays were ≥95% for COVID-19 only after the second week. ELISA and LFIA had somewhat lower PPVs. IgM exhibited insufficient predictive characteristics. An orthogonal testing approach provided PPVs ≥ 95% for patients with a moderate pretest probability (e.g., symptomatic patients), even for tests with a low single test performance. After the second week, NPVs of all but IgM assays were ≥95% for patients with low to moderate pretest probability. The confirmation of negative results using an orthogonal algorithm with another assay provided lower NPVs than the single assays. When interpreting results from SARS-CoV-2 tests, the pretest probability, time of blood draw, and assay characteristics must be carefully considered. An orthogonal testing approach increases the accuracy of positive, but not negative, predictions.


Subject(s)
Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Antibodies, Viral/blood , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques/methods , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Immunoassay/methods , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2 , Sensitivity and Specificity , Serologic Tests/methods
9.
Sci Rep ; 10(1): 19893, 2020 11 16.
Article in English | MEDLINE | ID: covidwho-927819

ABSTRACT

We assessed the performance of Abbott's SARS-CoV-2 IgG assay and the PanbioTM COVID-19 IgG/IgM rapid test device for the diagnosis of either active or cured COVID-19. Three cohorts of patients were chosen. Cohort 1, patients (n = 65) who attended the emergency department on March 30, 2020 with clinical suspicion of active COVID-19 (n = 56 with proven/probable COVID-19). Cohort 2, hospital workers (n = 92) who had either been (n = 40) or not (n = 52) diagnosed with proven/probable COVID-19 and were asymptomatic at the time of the sampling. Cohort 3, patients (n = 38) cared at the hospital before the start of the COVID-19 pandemic. Detection of serum antibodies was done using Abbott´s SARS-CoV-2 IgG assay and the PanbioTM COVID-19 IgG/IgM device. Both methods showed 98% agreement for IgG detection. No antibodies were detected in the 38 samples from hospitalized pre-COVID subjects. The diagnostic performance of IgGs detected by Abbott´s SARS-CoV-2 assay in Cohorts 1/2 was: sensitivity (60.7%/75%) and specificity (100%/84.6%). The diagnostic performance of IgM by PanbioTM COVID-19 in Cohorts 1/2 was: sensitivity (16%/17.5%) and specificity (100%/98.1%). We show that IgG detection alone is insufficient for the diagnosis of active or cured COVID-19. IgM detection has a limited diagnostic value.


Subject(s)
COVID-19 Serological Testing/standards , COVID-19/diagnosis , Reagent Kits, Diagnostic/standards , Aged , COVID-19/blood , Female , Humans , Male , Middle Aged , Sensitivity and Specificity
10.
BMC Infect Dis ; 20(1): 779, 2020 Oct 20.
Article in English | MEDLINE | ID: covidwho-883565

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has become a public health emergency of international concern. SARS-CoV-2 RNA detection is the diagnostic criterion for coronavirus disease 2019 (COVID-19). Nevertheless, RNA detection has many limitations, such as being time-consuming and cost-prohibitive, and it must be performed in specialized laboratories. Virus antibody detection is a routine method for screening for multiple viruses, but data about SARS-CoV-2 antibody detection are limited. METHOD: Throat swabs and blood were collected from 67 suspected SARS-CoV-2 infection patients at the Affiliated Hospital of Zunyi Medical University and Zunyi Fourth People's Hospital isolated observation departments. Throat swab samples were subjected to SARS-CoV-2 RNA detection by real-time PCR. Blood was used subjected to SARS-CoV-2 IgG/IgM detection by an enzyme-linked immunosorbent assay (ELISA) and gold immunochromatography assay (GICA). Blood underwent C-reactive protein detection by immunoturbidimetry, and white blood cells, neutrophil percentages and lymphocyte percentages were counted and calculated, respectively. Clinical symptoms, age and lifestyle habits (smoking and drinking) in all patients were recorded. Data were analysed using SPSS version 19. The results were confirmed by T and χ2 tests; correlations with detection results were analysed by kappa coefficients. Odds ratio (OR) and corrected OR values were analysed by logistic regression. P < 0.05 was considered statistically significant. RESULTS: Of the 67 patients included in this study, 26 were SARS-CoV-2 RNA-positive. GICA IgM sensitivity was 50.9% (13/26), and specificity was 90.2% (37/41). ELISA IgM sensitivity was 76.9% (20/26), and specificity was 90.2% (37/41). ELISA IgG sensitivity was 76.9% (20/26), and specificity was 95.1% (39/41). The kappa coefficients between RNA detection and ELISA IgG, ELISA IgM, and GICA IgM results were 0.741 (P < 0.01), 0.681 (P < 0.01) and 0.430 (P < 0.01), respectively. CONCLUSION: Among the candidate blood indicators, serum IgG and IgM detected by ELISA had the best consistency and validity when compared with standard RNA detection; these indicators can be used as potential preliminary screening tools to identify those who should undergo nucleic acid detection in laboratories without RNA detection abilities or as a supplement to RNA detection.


Subject(s)
Betacoronavirus/genetics , Betacoronavirus/immunology , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Pneumonia, Viral/diagnosis , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Adult , Aged , Aged, 80 and over , Antibodies, Viral/blood , COVID-19 , COVID-19 Testing , Cohort Studies , Coronavirus Infections/virology , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , SARS-CoV-2 , Sensitivity and Specificity
11.
Clin Chim Acta ; 510: 790-795, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-778568

ABSTRACT

BACKGROUND: While the diagnosis of SARS-CoV-2 infection is primarily based on detection of viral RNA, the detection of SARS-CoV-2 antibodies is useful for assessing past prevalence of the disease, and in corroborating a current infection in challenging cases. Sensitive and specific immunoassays provide the ability to identify exposure to SARS-CoV-2, to determine seroconversion, to confirm eligibility for donation of convalescent plasma as well as play an essential part in epidemiological studies. We report on the validation of the Ansh Laboratories SARS-CoV-2 IgG and SARS-CoV-2 IgM ELISA immunoassays. These assays were evaluated for detection of anti-SARS-CoV-2 IgG and IgM antibodies for clinical use in our hospital as part of an orthogonal testing algorithm recommended by the CDC. METHODS: Diagnostic specificity and sensitivity of the IgG and IgM ELISA assays were tested using samples confirmed to be negative or positive for COVID-19 by RT-PCR. We also evaluated precision, analytical interference, and cross-reactivity with known cases of infection with other viruses. Additionally, we validated concordance with molecular and other serological testing and evaluated seroconversion in our patient population. RESULTS: The IgG and IgM ELISA assays showed acceptable precision, were robust to analytical interference and did not exhibit cross reactivity with specimens positive for common respiratory viruses. Both assays exhibited 95% agreement with a primary screening serological assay utilized at our institution as well as with a reference laboratory semi-quantitative method. Concordance with RT-PCR was excellent > 6 days after symptom onset (100%). CONCLUSIONS: The Ansh SARS-CoV-2 ELISA assays have good analytical performance suitable for clinical use.


Subject(s)
Betacoronavirus/immunology , Enzyme-Linked Immunosorbent Assay/methods , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Epitopes/immunology , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , SARS-CoV-2
12.
PLoS Pathog ; 16(9): e1008796, 2020 09.
Article in English | MEDLINE | ID: covidwho-760712

ABSTRACT

There is an urgent need for effective treatment and preventive vaccine to contain this devastating global pandemic, which requires a comprehensive understanding of humoral responses specific to SARS-CoV-2 during the disease progression and convalescent phase of COVID-19 patients. We continuously monitored the serum IgM and IgG responses specific to four SARS-CoV-2 related antigens, including the nucleoprotein (NP), receptor binding domain (RBD), S1 protein, and ectodomain (ECD) of the spike protein among non-severe and severe COVID-19 patients for seven weeks since disease onset. Most patients generated humoral responses against NP and spike protein-related antigens but with their distinct kinetics profiles. Combined detection of NP and ECD antigens as detecting antigen synergistically improved the sensitivity of the serological assay, compared to that of using NP or RBD as detection antigen. 80.7% of convalescent sera from COVID-19 patients revealed that the varying extents of neutralization activities against SARS-CoV-2. S1-specific and ECD-specific IgA responses were strongly correlated with the neutralization activities in non-severe patients, but not in severe patients. Moreover, the neutralizing activities of the convalescent sera were shown to significantly decline during the period between 21 days to 28 days after hospital discharge, accompanied by a substantial drop in RBD-specific IgA response. Our data provide evidence that are crucial for serological testing, antibody-based intervention, and vaccine design of COVID-19.


Subject(s)
Antibodies, Neutralizing/pharmacology , Antibodies, Viral/pharmacology , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Betacoronavirus/pathogenicity , COVID-19 , Humans , Immunoglobulin G/blood , Longitudinal Studies , Pandemics , SARS-CoV-2 , Serologic Tests , Spike Glycoprotein, Coronavirus/immunology
13.
Clin Chem Lab Med ; 58(12): 2121-2130, 2020 08 27.
Article in English | MEDLINE | ID: covidwho-732982

ABSTRACT

Objectives Assessment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection prevalence and immunity is cornerstones in the fight against COVID-19 pandemic. For pandemic control, reliable assays for the detection of anti-SARS-CoV-2 antibodies are required. This pilot external quality assessment (EQA) scheme aimed to independently assess the participants' clinical performance of anti-SARS-CoV-2 testing, to identify shortcomings in clinical practice and to evaluate the suitability of the scheme format. Methods The EQA scheme consisted of eight serum samples with variable reactivity against SARS-CoV-2 intended for the analysis of anti-SARS-CoV-2 immunoglobulin (Ig)G, IgA, and IgM antibodies. Laboratories reported: (1) results for each sample and the respective method, (2) raw data from replicate testing of each sample. Results The 16 selected pilot EQA participants reported 294 interpreted results and 796 raw data results from replicate testing. The overall error rate for the anti-SARS-CoV-2 IgG, IgA, and IgM tests was 2.7, 6.9, and 16.7%, respectively. While the overall diagnostic specificity was rated as very high, sensitivity rates between 67 and 98% indicate considerable quality differences between the manufacturers, especially for IgA and IgM. Conclusions Even the results reported by the small number of participants indicate a very heterogeneous landscape of anti-SARS-CoV-2 serological testing. Differences of available tests and the individual performance of laboratories result in a success rate of 57.1% with one laboratory succeeding for all three antibody-classes. These results are an incentive for laboratories to participate in upcoming open EQA schemes that are needed to achieve a harmonization of test results and to improve serological testing.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Serologic Tests , Antibodies, Viral/immunology , Humans , Pilot Projects , Quality Control , SARS-CoV-2
14.
Emerg Microbes Infect ; 9(1): 2020-2029, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-720915

ABSTRACT

COVID-19 is caused by SARS-CoV-2 infection and was initially discovered in Wuhan. This outbreak quickly spread all over China and then to more than 20 other countries. SARS-CoV-2 fluorescent microsphere immunochromatographic test strips were prepared by the combination of time-resolved fluorescence immunoassay with a lateral flow assay. The analytical performance and clinical evaluation of this testing method was done and the clinical significance of the testing method was verified. The LLOD of SARS-CoV-2 antibody IgG and IgM was 0.121U/L and 0.366U/L. The specificity of IgM and IgG strips in healthy people and in patients with non-COVID-19 disease was 94%, 96.72% and 95.50%, 99.49%, respectively; and sensitivity of IgM and IgG strips for patients during treatment and follow-up was 63.02%, 37.61% and 87.28%, 90.17%, respectively. The SARS-CoV-2 antibody test strip can provide rapid, flexible and accurate testing, and is able to meet the clinical requirement for rapid on-site testing of virus. The ability to detect IgM and IgG provided a significant benefit for the detection and prediction of clinical course with COVID-19 patients.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoglobulin G/analysis , Immunoglobulin M/analysis , COVID-19/immunology , Fluorescent Antibody Technique , Humans , SARS-CoV-2/immunology , Sensitivity and Specificity
15.
Int Immunopharmacol ; 88: 106861, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-689157

ABSTRACT

Corona Virus Disease 2019 (COVID-19) has spread rapidly to more than 215 countries, with over 11.91 million reported cases and more than 540,000 deaths. Rapid diagnosis remains a bottleneck for containing the epidemic. We used an automated chemiluminescent immunoassay to detect serum IgM and IgG antibodies to the 2019-nCoV in 742 subjects, so as to observe the dynamic process of antibody production in COVID-19 disease and seroepidemiology in different populations. Patients with COVID-19 were reactive (positive) for specific antibodies within 3-15 days after onset of symptoms. Specific IgM and IgG levels increased with the progression of the disease. The areas under the receiver operating characteristic curves for IgM and IgG were 0.984 and 1.000, respectively. This antibody detection assay had good sensitivity and specificity. The understanding of the dynamic serological changes of COVID-19 patients and the seroepidemiological situation of the population will be helpful to further control the epidemic of COVID-19.


Subject(s)
Antibodies, Viral/blood , Clinical Laboratory Techniques , Coronavirus Infections/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Pneumonia, Viral/blood , Reverse Transcriptase Polymerase Chain Reaction , Adult , Betacoronavirus/immunology , COVID-19 , COVID-19 Testing , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/immunology , SARS-CoV-2 , Sensitivity and Specificity , Seroepidemiologic Studies , Severity of Illness Index , Young Adult
16.
Biosens Bioelectron ; 165: 112454, 2020 Oct 01.
Article in English | MEDLINE | ID: covidwho-651785

ABSTRACT

The rapidly spreading outbreak of COVID-19 disease is caused by the SARS-CoV-2 virus, first reported in December 2019 in Wuhan, China. As of June 17, 2020, this virus has infected over 8.2 million people but ranges in symptom severity, making it difficult to assess its overall infection rate. There is a need for rapid and accurate diagnostics to better monitor and prevent the spread of COVID-19. In this review, we present and evaluate two main types of diagnostics with FDA-EUA status for COVID-19: nucleic acid testing for detection of SARS-CoV-2 RNA, and serological assays for detection of SARS-CoV-2 specific IgG and IgM patient antibodies, along with the necessary sample preparation for accurate diagnoses. In particular, we cover and compare tests such as the CDC 2019-nCoV RT-PCR Diagnostic Panel, Cellex's qSARS-CoV-2 IgG/IgM Rapid Test, and point-of-care tests such as Abbott's ID NOW COVID-19 Test. Antibody testing is especially important in understanding the prevalence of the virus in the community and to identify those who have gained immunity. We conclude by highlighting the future of COVID-19 diagnostics, which include the need for quantitative testing and the development of emerging biosensors as point-of-care tests.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Immunoassay/methods , Pneumonia, Viral/diagnosis , Point-of-Care Testing , Reverse Transcriptase Polymerase Chain Reaction/methods , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , COVID-19 , Coronavirus Infections/blood , Humans , Immunoassay/instrumentation , Immunoglobulin G/analysis , Immunoglobulin G/blood , Immunoglobulin M/analysis , Immunoglobulin M/blood , Pandemics , Pneumonia, Viral/blood , RNA, Viral/analysis , Reverse Transcriptase Polymerase Chain Reaction/instrumentation , SARS-CoV-2 , Specimen Handling/instrumentation , Specimen Handling/methods , United States , United States Food and Drug Administration
17.
J Infect Dis ; 222(2): 189-193, 2020 06 29.
Article in English | MEDLINE | ID: covidwho-643587

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel ß-coronavirus, causes severe pneumonia and has spread throughout the globe rapidly. The disease associated with SARS-CoV-2 infection is named coronavirus disease 2019 (COVID-19). To date, real-time reverse-transcription polymerase chain reaction (RT-PCR) is the only test able to confirm this infection. However, the accuracy of RT-PCR depends on several factors; variations in these factors might significantly lower the sensitivity of detection. METHODS: In this study, we developed a peptide-based luminescent immunoassay that detected immunoglobulin (Ig)G and IgM. The assay cutoff value was determined by evaluating the sera from healthy and infected patients for pathogens other than SARS-CoV-2. RESULTS: To evaluate assay performance, we detected IgG and IgM in the sera from confirmed patients. The positive rate of IgG and IgM was 71.4% and 57.2%, respectively. CONCLUSIONS: Therefore, combining our immunoassay with real-time RT-PCR might enhance the diagnostic accuracy of COVID-19.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Immunoenzyme Techniques/methods , Pneumonia, Viral/diagnosis , Serologic Tests/methods , Adult , COVID-19 , COVID-19 Testing , COVID-19 Vaccines , Coronavirus Infections/immunology , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Luminescent Measurements , Male , Middle Aged , Pandemics , Peptides/immunology , Pneumonia, Viral/immunology , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Sensitivity and Specificity , Viral Proteins/immunology
18.
J Infect Public Health ; 13(10): 1453-1455, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-641625

ABSTRACT

Since the outbreak of novel coronavirus (SARS-CoV-2)-infected pneumonia (COVID-19), numerous medical staff are fighting on the frontline. However, the possibility of occult infection in medical staff is ignored in many recent studies. Herein, we collected data in a COVID-19 designated hospital from January 22, 2020 to March 10, 2020. A total of 33 medical staff had at least one nucleic acid test of throat swab, immunoglobulin G (IgG) or IgM serum antibody test, and chest computed tomography (CT), were enrolled. Finally, we identified 25 cases (75.8%) were isolated for hospitalized treatment after positive virus detection. In addition, 4 cases who were all negative for nucleic acid test detection with no clinical symptoms, and none of their chest CT were abnormal. However, the results of serum IgG or IgM antibody test in these 4 cases were positive, suggesting the presence of occult infection. In conclusion, data from our single center indicated that SARS-CoV-2 had a high medical infection rate (29/33 = 87.9%) and might have a potential risk of occult infection.


Subject(s)
Antibodies, Viral/blood , Asymptomatic Infections , Betacoronavirus/immunology , Coronavirus Infections/diagnosis , Hospitals, Special , Medical Staff, Hospital/statistics & numerical data , Pneumonia, Viral/diagnosis , RNA, Viral/blood , Adult , Betacoronavirus/genetics , COVID-19 , China/epidemiology , Coronavirus Infections/epidemiology , Female , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Pandemics , Pneumonia, Viral/epidemiology , Radiography, Thoracic , SARS-CoV-2 , Tomography, X-Ray Computed
19.
J Clin Microbiol ; 58(6)2020 05 26.
Article in English | MEDLINE | ID: covidwho-590624

ABSTRACT

At present, PCR-based nucleic acid detection cannot meet the demands for coronavirus infectious disease (COVID-19) diagnosis. Two hundred fourteen confirmed COVID-19 patients who were hospitalized in the General Hospital of Central Theater Command of the People's Liberation Army between 18 January and 26 February 2020 were recruited. Two enzyme-linked immunosorbent assay (ELISA) kits based on recombinant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (rN) and spike protein (rS) were used for detecting IgM and IgG antibodies, and their diagnostic feasibility was evaluated. Among the 214 patients, 146 (68.2%) and 150 (70.1%) were successfully diagnosed with the rN-based IgM and IgG ELISAs, respectively; 165 (77.1%) and 159 (74.3%) were successfully diagnosed with the rS-based IgM and IgG ELISAs, respectively. The positive rates of the rN-based and rS-based ELISAs for antibody (IgM and/or IgG) detection were 80.4% and 82.2%, respectively. The sensitivity of the rS-based ELISA for IgM detection was significantly higher than that of the rN-based ELISA. We observed an increase in the positive rate for IgM and IgG with an increasing number of days post-disease onset (d.p.o.), but the positive rate of IgM dropped after 35 d.p.o. The positive rate of rN-based and rS-based IgM and IgG ELISAs was less than 60% during the early stage of the illness, 0 to 10 d.p.o., and that of IgM and IgG was obviously increased after 10 d.p.o. ELISA has a high sensitivity, especially for the detection of serum samples from patients after 10 d.p.o., so it could be an important supplementary method for COVID-19 diagnosis.


Subject(s)
Betacoronavirus/immunology , Clinical Laboratory Techniques/methods , Coronavirus Infections/immunology , Coronavirus Infections/virology , Enzyme-Linked Immunosorbent Assay/methods , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Spike Glycoprotein, Coronavirus/immunology , COVID-19 , COVID-19 Testing , Coronavirus Infections/diagnosis , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin M/blood , Immunoglobulin M/immunology , Pandemics , SARS-CoV-2
20.
J Clin Virol ; 128: 104413, 2020 07.
Article in English | MEDLINE | ID: covidwho-175902

ABSTRACT

INTRODUCTION: Several SARS-CoV-2 immunoassays have been developed recently. The purpose of this study was to assess the performance of five immunoassays for the detection of SARS-CoV-2 antibodies. METHODS: Two quantitative automated immunoassays (Maglumi™2019-n-Cov IgG and IgM and Euroimmun Anti-SARS-CoV-2 IgG and IgA assays) and three lateral flow rapid tests were performed. This retrospective study included 200 residual sera from patients and healthy volunteers. Case serum samples (n = 128) were obtained from COVID-19 patients confirmed by RT-qPCR and CT-scan. Days since onset of symptoms was collected from their medical records. Control non-SARS-CoV-2 samples (n = 72) were obtained from anonymous stored residual serum samples. RESULTS: Maglumi™ IgG/IgM tests showed overall less sensitivity than Euroimmun IgG/IgA test (84.4 % versus 64.3 %). Both tests showed similar specificities of IgG at 99 % and 100 %, respectively. The results from the lateral flow assays were easily interpretable with unambiguous coloured reading bands. The overall sensitivity of the three tests was similar (around 70 %) without any significant differences. The sensitivity of the three lateral flow assays and also of the serological quantitative assays increased during the second week after symptom onset and all reached similar values (91 %-94 %) after 14 days. CONCLUSION: This study shows accurate and equivalent performance of the five serological antibody assays (ELISA, CLIA and three lateral flow tests) in detecting SARS-CoV-2 antibodies 14 days after the onset of COVID-19 symptoms. This is compatible with their application in specific clinical contexts and in determining epidemiological strategies for the COVID-19 pandemic.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Immunoglobulin A/blood , Immunoglobulin G/blood , Pandemics , Pneumonia, Viral/diagnosis , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/virology , Humans , Immunoassay/methods , Pneumonia, Viral/virology , Retrospective Studies , SARS-CoV-2 , Sensitivity and Specificity
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