scholarly journals Kinetics and performance of the Abbott Architect SARS-CoV-2 IgG antibody assay

2020 ◽  
Author(s):  
Fergus Hamilton ◽  
Peter Muir ◽  
Marie Attwood ◽  
Alan Noel ◽  
Barry Vipond ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Clinical Settings ◽  
Antibody Testing ◽  
Antibody Assay ◽  
Igg Antibody ◽  
Negative Results ◽  
Hospitalised Patients ◽  
And Performance ◽  
Negative Controls ◽  
Abbott Architect

ObjectivesTo assess the performance (sensitivity and specificity) of the Abbott Architect SARS-CoV-2 IgG antibody assay across three clinical settings.MethodsAntibody testing was performed on three clinical cohorts of COVID-19 disease: hospitalised patients with PCR confirmation, hospitalized patients with a clinical diagnosis but negative PCR, and symptomatic healthcare workers (HCW’s). Pre-pandemic respiratory infection sera were tested as negative controls. The sensitivity of the assay was calculated at different time points (<5 days, 5-9 days, 10-14 days, 15-19 days, >20 days, >42 days), and compared between cohorts.ResultsPerformance of the Abbot Architect SARS-CoV-2 assay varied significantly between cohorts. For PCR confirmed hospitalised patients (n = 114), early sensitivity was low: <5 days: 44.4% (95%CI: 18.9%-73.3%), 5-9 days: 32.6% (95%CI, 20.5%-47.5%), 10-14 days: 65.2% (95% CI 44.9%-81.2%), 15-20 days: 66.7% (95% CI: 39.1%-86.2%) but by day 20, sensitivity was 100% (95%CI, 86.2-100%).In contrast, 17 out of 114 symptomatic healthcare workers tested at >20 days had negative results, generating a sensitivity of 85.1% (95%CI, 77.4% - 90.5%). All pre-pandemic sera were negative, a specificity of 100%. Seroconversion rates were similar for PCR positive and PCR negative hospitalised cases.ConclusionsThe sensitivity of the Abbot Architect SARS-CoV-2 IgG assay increases over time, with sensitivity not peaking until 20 days post symptoms. Performance varied markedly by setting, with sensitivity significantly worse in symptomatic healthcare workers than in the hospitalised cohort. Clinicians, policymakers, and patients should be aware of the reduced sensitivity in this setting.

scholarly journals Kinetics and performance of the Abbott architect SARS-CoV-2 IgG antibody assay

2020 ◽  
Vol 81 (6) ◽  
pp. e7-e9 ◽  
Author(s):  
Fergus Hamilton ◽  
Peter Muir ◽  
Marie Attwood ◽  
Alan Noela Barry Vipond ◽  
Richard Hopes ◽  
...  
Keyword(s):  
Antibody Assay ◽  
Igg Antibody ◽  
And Performance ◽  
Abbott Architect

scholarly journals Stringent thresholds in SARS-CoV-2 IgG assays lead to under-detection of mild infections

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
David W. Eyre ◽  
Sheila F. Lumley ◽  
Denise O’Donnell ◽  
Nicole E. Stoesser ◽  
Philippa C. Matthews ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Antibody Assay ◽  
Diagnostic Thresholds ◽  
Assay Performance ◽  
Hospitalised Patients ◽  
Antibody Assays ◽  
Chemiluminescent Microparticle Immunoassay ◽  
Result Interpretation ◽  
Test Probability ◽  
Abbott Architect

Abstract Background Thresholds for SARS-CoV-2 antibody assays have typically been determined using samples from symptomatic, often hospitalised, patients. In this setting the sensitivity and specificity of the best performing assays can both exceed 98%. However, antibody assay performance following mild infection is less clear. Methods We assessed quantitative IgG responses in a cohort of healthcare workers in Oxford, UK, with a high pre-test probability of Covid-19, in particular the 991/11,475(8.6%) who reported loss of smell/taste. We use anosmia/ageusia and other risk factors as probes for Covid-19 infection potentially undiagnosed by immunoassays by investigating their relationship with antibody readings either side of assay thresholds. Results The proportion of healthcare workers reporting anosmia/ageusia increased at antibody readings below diagnostic thresholds using an in-house ELISA (n = 9324) and the Abbott Architect chemiluminescent microparticle immunoassay (CMIA; n = 11,324): 426/906 (47%) reported anosmia/ageusia with a positive ELISA, 59/449 (13.1%) with high-negative and 326/7969 (4.1%) with low-negative readings. Similarly, by CMIA, 518/1093 (47.4%) with a positive result reported anosmia/ageusia, 106/686 (15.5%) with a high-negative and 358/9563 (3.7%) with a low-negative result. Adjusting for the proportion of staff reporting anosmia/ageusia suggests the sensitivity of both assays in mild infection is lower than previously reported: Oxford ELISA 89.8% (95%CI 86.6–92.8%) and Abbott CMIA 79.3% (75.9–82.7%). Conclusion Following mild SARS-CoV-2 infection 10–30% of individuals may have negative immunoassay results. While lowered diagnostic thresholds may result in unacceptable specificity, our findings have implications for epidemiological analyses and result interpretation in individuals with a high pre-test probability. Samples from mild PCR-confirmed infections should be included in SARS-CoV-2 immunoassay evaluations.

scholarly journals Prevalence of SARS-CoV-2 Antibodies Among Healthcare Workers at a Tertiary Academic Hospital in New York City

2020 ◽  
Author(s):  
Mayce Mansour ◽  
Emily Levin ◽  
Kimberly Muellers ◽  
Kimberly Stone ◽  
Rao Mendu ◽  
...  
Keyword(s):  
New York ◽  
Healthcare Workers ◽  
Igg Antibodies ◽  
Academic Hospital ◽  
Antibody Testing ◽  
Igg Antibody ◽  
Frontline Staff ◽  
High Exposure ◽  
Cdc Guidelines ◽  
Viral Illness

Background: SARS-CoV-2 antibody testing is important for understanding immunity prevalence, and may have implications for healthcare workers (HCW) during the SARS-CoV-2 pandemic. Methods: We conducted immunologic testing of healthcare workers to determine the prevalence of SARS-CoV-2 IgG in this population. HCW were advised to wait at least two weeks from time of symptom onset or suspected exposure before undergoing testing. All participants were self-reported asymptomatic for at least three days at the time of testing. Results: Two hundred eighty-five samples were collected from March 24, 2020 to April 4, 2020. The average age of participants was 38 years (range 18-84), and 54% were male. Thirty-three percept tested IgG positive, 3% tested weakly positive, and 64% tested negative. Neither age nor sex was associated with antibody development. Conclusion: Thirty-six percent of HCW had IgG antibodies to SARS-CoV-2, reflecting the high exposure of inpatient and ambulatory frontline staff to this viral illness, most of whom had minimal symptoms and were working in the weeks preceding testing. While we continue to recommend standard protective precautions per CDC guidelines for all HCW, HCW with SARS-CoV-2 IgG may become our safest frontline providers as we learn if our IgG antibodies confer immunity. Knowing IgG antibody status may ease concerns regarding personal risk as this pandemic continues.

scholarly journals Stringent thresholds for SARS-CoV-2 IgG assays result in under-detection of cases reporting loss of taste/smell

2020 ◽  
Author(s):  
David W Eyre ◽  
Sheila F Lumley ◽  
Denise O'Donnell ◽  
Nicole E Stoesser ◽  
Philippa C Matthews ◽  
...  
Keyword(s):  
Asymptomatic Infection ◽  
Negative Results ◽  
Diagnostic Thresholds ◽  
Assay Performance ◽  
Hospitalised Patients ◽  
Antibody Assays ◽  
Antibody Titres ◽  
Chemiluminescent Microparticle Immunoassay ◽  
Test Probability ◽  
Abbott Architect

Thresholds for SARS-CoV-2 antibody assays have typically been determined using samples from symptomatic, often hospitalised, patients. Assay performance following mild/asymptomatic infection is unclear. We assessed IgG responses in asymptomatic healthcare workers with a high pre-test probability of Covid-19, e.g. 807/9292(8.9%) reported loss of smell/taste. The proportion reporting anosmia/ageusia increased at antibody titres below diagnostic thresholds for both an in-house ELISA and the Abbott Architect chemiluminescent microparticle immunoassay (CMIA): 424/903(47%) reported anosmia/ageusia with a positive ELISA, 59/387(13.2%) with high-negative titres, and 324/7943(4.1%) with low-negative results. Adjusting for the proportion of staff reporting anosmia/ageusia suggests the sensitivity of both assays is lower than previously reported: Oxford ELISA 90.8% (95%CI 86.1-92.1%) and Abbott CMIA 80.9% (77.5-84.3%). However, the sensitivity may be lower if some anosmia/ageusia in those with low-negative titres is Covid-19-associated. Samples from individuals with mild/asymptomatic infection should be included in SARS-CoV-2 immunoassay evaluations. Reporting equivocal SARS-CoV-2 antibody results should be considered.

scholarly journals SARS-CoV-2 Seroprevalence in Relation to Timing of Symptoms

2020 ◽  
Author(s):  
Joseph Ebinger ◽  
Gregory J. Botwin ◽  
Christine M. Albert ◽  
Mona Alotaibi ◽  
Moshe Arditi ◽  
...  
Keyword(s):  
Antibody Testing ◽  
Antibody Assay ◽  
Igg Antibody ◽  
Symptom Clustering

Of individuals with SARS-CoV-2 IgG antibody testing performed, those who contemporaneously experienced a cluster of Covid-19 relevant symptoms in the 1-2 months preceding the antibody assay were more likely to test positive whereas those who experienced the symptom clustering in the prior 3-6 months were more likely to test negative. These findings suggest that antibodies likely wane over a period of months, particularly in relation to the timing of symptoms.

scholarly journals SARS-CoV-2 IgG Surveillance in Asymptomatic Blood Donors and Health Workers

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Tulika Chandra ◽  
Devisha Agarwal ◽  
D. Himanshu ◽  
Mallika Agarwal ◽  
Bipin Puri
Keyword(s):  
General Population ◽  
Healthcare Workers ◽  
Blood Donors ◽  
Health Workers ◽  
World Health ◽  
Age Group ◽  
Antibody Testing ◽  
Igg Antibody ◽  
First Case ◽  
Medical Healthcare

Background and Objectives. SARS-CoV-2 virus has caused a global pandemic as declared by the World Health Organisation (WHO) in March 2020. In India, the first case was reported in Kerala on the 30th of January, and since then, many states are active but some are showing flattening. Following the seroprevalence testing in healthy blood donors, we can monitor the spread of the virus among healthy people, thus eventually leading to implementing strategies to reduce the spread. Thus, a need was felt to conduct a study to assess the IgG antibody status in healthcare workers differentiating those who were in COVID-19 and others in non-COVID-19 emergency duties during this pandemic. Materials and Methods. 2085 blood donors were allowed to donate blood only after fulfilling all the criteria laid down by the FDA of India with additional history of excluding COVID-19 suspects. IgG antibody testing was performed by chemiluminescence, and results were noted along with their reactive status. Their reactive status was analyzed with donor information to get an idea of the risk parameters for COVID-19. Medical healthcare workers in whom the study was carried out were 560, out of which 114 had worked in COVID-19 duties and 446 had worked in non-COVID-19 emergencies areas. COVID-19 area duties were further subdivided into triage, holding area, isolation, and COVID-19-related duties. The samples were run on architect i2000 and evaluated for their plasma immunoglobulin G. Results. Amongst the asymptomatic blood donors, 1.9% was found to be COVID-19 IgG antibody positive. It was observed that maximum COVID-19 IgG positivity (57.1%) was seen in the age group 18–29 years followed by 26.2% in the age group 30–39 years. Donors in the age group 40–49 years showed antibody positivity of 16.7%, and no antibody-positive donors were found above 50 years of age. COVID-19 IgG positivity was maximum in replacement donors (61.9%) followed by family donors (28.6%) and least involuntary donors (0.6%) Blood donors who showed high IgG positivity were mainly of labor class. Antibody IgG testing on medical healthcare workers showed 2.3% positivity. The healthcare workers who were posted in COVID-19 duties showed 4.8% positivity in the holding area (waiting area with the treatment of patients till their RT PCR report comes) and 5.7% in other COVID-19 areas related to laboratory work. Healthcare workers doing duties in COVID-19 areas showed 2.7% positivity, while those doing duties in non-COVID-19 emergency areas showed a positivity of 2.2%. Conclusion. Our study shows that the prevalence of detectable antibodies was low in the general population in India and many patients were asymptomatic as seen in the blood donors, especially the labor class. Maximum exposure was present in young healthy males of labor class who remained asymptomatic. The healthcare workers were more exposed to COVID-19 as compared to the general population probably due to lack of precaution and awareness. Those doing non-COVID-19 duties were also exposed appreciably and needed to take all the precautions required for COVID-19 duties.

scholarly journals Potential False-Positive and False-Negative Results for COVID-19 IgG/IgM Antibody Testing After Heat-Inactivation

2021 ◽  
Vol 7 ◽  
Author(s):  
Jie Lin ◽  
Wei Dai ◽  
Weiwei Li ◽  
Li Xiao ◽  
Tao Luo ◽  
...  
Keyword(s):  
False Negative ◽  
Antibody Detection ◽  
Heat Inactivation ◽  
Antibody Testing ◽  
Igg Antibody ◽  
Igm Antibody ◽  
Negative Results ◽  
False Negative Results ◽  
Specific Igg ◽  
Potential False Positive

Objectives: With the worldwide spread of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), various antibody detection kits have been developed to test for SARS-CoV-2– specific IgG, IgM, and total antibody. However, the use of different testing methods under various heat-inactivation conditions might affect the COVID-19 detection results.Methods: Seven different antibody detection kits produced by four manufacturers for detection of SARS-CoV-2 IgG, IgM, and total antibody were tested at Wuhan Huoshenshan Hospital, China. Most of the kits used the indirect immunity, capture, and double-antigen sandwich methods. The effects of various heat-inactivation conditions on SARS-CoV-2-specific IgG, IgM, and total antibody detection were analyzed for the different test methods.Results: Using the indirect immunity method, values for SARS-CoV-2 IgG antibody significantly increased and those for IgM antibody decreased with increasing temperature of heat-inactivation using indirect immunity method. However, values for SARS-CoV-2 IgM and total antibody showed no change when the capture and double-antigen sandwich methods were used. The changes in IgG and IgM antibody values with the indirect immunity method indicated that heat-inactivation could affect COVID-19 detection results obtained using this method. In particular, 18 (22.2%) SARS-CoV-2 IgM positive samples were detected as negative with heat-inactivation at 65°C for 30 min, and one (25%) IgG negative sample was detected as positive after heat-inactivation at 56°C for 60 min and 60°C for 30 min.Conclusions: Heat-inactivation could increase SARS-CoV-2 IgG antibody values, and decrease IgM antibody values, causing potential false-positive or false-negative results for COVID-19 antibody detection using the indirect immunity method. Thus, before conducting antibody testing, the testing platforms should be evaluated in accordance with the relevant requirements to ensure accurate COVID-19 detection results.

scholarly journals EXPRESS: Comparison of four high throughput, automated immunoassays for the detection of SARS-CoV-2 antibodies

2021 ◽  
pp. 000456322110157
Author(s):  
Jane Oakey ◽  
Shonagh Haslam ◽  
Andrew Peter Brown ◽  
Janet Eglin ◽  
Brittany Houghton ◽  
...  
Keyword(s):  
General Practice ◽  
High Throughput ◽  
Healthcare Workers ◽  
Recent Infection ◽  
Practice Population ◽  
Hospitalised Patients ◽  
Abbott Architect ◽  
Roche Cobas

Background: A number of immunoassays have been developed to measure antibodies specific to SARS-CoV-2. More data is required on their comparability, particularly amongst those with milder infections and in the general practice population. The aim of this study was to compare four high throughput automated anti SARS-CoV-2 assays using samples collected from hospitalised patients and healthcare workers with confirmed SARS-CoV-2 infection. In addition, we collected general practice samples to compare antibody results and determine seroprevalence. Methods: Samples were collected from 57 hospitalised patients and 9 healthcare workers at 14 days and at 28 days following confirmed SARS-CoV-2 infection. Samples were also collected from 225 patients presenting to general practice. Four assays were used: Abbott Architect IgG, Beckman Coulter DxI 800 IgG, Roche Cobas e801 total antibody and Siemens Advia Centaur XPT total antibody. Results: All 4 assays showed concordance at 14 days in 83.9% of hospitalised patients and in 66.7% of healthcare workers. All 4 assays showed concordance at 28 days in 88.4% of hospitalised patients and 77.8% of healthcare workers. The sensitivity to detect recent infection was higher for the IgG assays than the total assays. All 4 assays showed concordance of 95.1% in the general practice population. Seroprevalence ranged from 4.9-5.8% depending on the assay used. Conclusions: All 4 assays showed excellent comparability but it may be possible to obtain a negative result for any of the anti SARS-CoV-2 assays in patients with confirmed previous SARS-CoV-2 infection. An equivocal range would be useful for all anti SARS-CoV-2 assays.

scholarly journals 501. Serum IgG Antibody Testing Against Severe Acute Respiratory Syndrome Coronavirus 2 in Healthcare Workers

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S316-S316
Author(s):  
Joy J Juskowich ◽  
Ziad Dimachkie ◽  
Mary Fanning ◽  
Arif R Sarwari ◽  
Nathan M Lerfald ◽  
...  
Keyword(s):  
High Risk ◽  
West Virginia ◽  
Healthcare Workers ◽  
Low Risk ◽  
Antibody Testing ◽  
Serum Samples ◽  
Igg Antibody ◽  
Respiratory Therapists ◽  
Percent Positivity ◽  
Risk Areas

Abstract Background With the COVID-19 pandemic, many changes were made in healthcare institutions including but not limited to canceling elective surgeries, limiting face-to-face clinic visits, and implementing visitor restrictions. Phased reopening began at West Virginia University (WVU) Medicine on May 25, 2020. While preparing for transition, concern was raised regarding potential for more employee exposures to persons with SARS-CoV-2 infection. In West Virginia (WV), we did not get the predicted surge of SARS-CoV-2. Current cumulative percent positivity for SARS-CoV-2 PCR in WV is 2332 positives of 133,142 tests (1.75%). We provided appropriate personal protective equipment (PPE), including controlled air purifying respirators for all healthcare workers (HCW) caring for persons with suspected or confirmed COVID-19 from the beginning. Policies requiring masks for all HCW and patients took effect on March 27, 2020 and April 29, 2020, respectively. We hypothesized that due to appropriate PPE use there would be no difference in SARS-CoV-2 antibody positivity in HCW working in high versus low risk areas. Methods Serum samples from 1042 randomly selected HCW across 4 WVU Medicine hospitals, ranging from 170 to 690 beds with 121 cumulative SARS-CoV-2 PCR positive patients at the time of the study, were tested for SARS-CoV-2 IgG between May 26, 2020 and June 5, 2020. Physicians, nurses, and respiratory therapists were characterized as high or low risk based on work location. Environmental services (EVS) workers were included but not risk-stratified. A questionnaire was used to obtain information on demographics, chronic medical conditions, symptoms, and exposures. Results SARS-CoV-2 IgG was positive in 9 of 1042 (0.86%) randomly selected HCW. Seroprevalence was lower in high risk 5/835 (0.60%) versus low risk 4/176 (2.27%) group. This was not statistically significant. No EVS workers tested positive 0/31 (0%). Of 9 HCW who tested positive, 2 had previously tested positive for SARS-CoV-2 PCR. Conclusion SARS-CoV-2 IgG seroprevalence in a large sample of HCW across 4 WVU Medicine hospitals was low (0.86%). Low seroprevalence among HCW in high risk areas may be related to appropriate PPE use. Seroprevalence in HCW not caring for patients with COVID-19 could be from community or other inadvertent exposure. Disclosures All Authors: No reported disclosures

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