scholarly journals Sensitivity of SARS-CoV-2 antibody tests with late convalescent sera

2021 ◽  
Author(s):  
Judith Kannenberg ◽  
Carolin Schnurra ◽  
Nina Reiners ◽  
Reinhard Henschler ◽  
Raymund Buhmann ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Antibody Test ◽  
Igg Antibody ◽  
Time Points ◽  
Igm Antibodies ◽  
Antibody Assays ◽  
Previous Infection ◽  
Antibody Levels ◽  
Antibody Tests ◽  
Over Time

SARS-CoV-2-specific IgM antibodies wane during the first three months after infection and IgG antibody levels decline. This may limit the ability of antibody tests to identify previous SARS CoV-2 infection at later time points. To examine if the sensitivity of antibody tests falls off, we compared the sensitivity of two nucleoprotein-based antibody tests, the Roche Elecsis II Anti-SARS-CoV-2 and the Abbott SARS-CoV-2 IgG assay and three glycoprotein-based tests, the Abbott SARS-CoV-2 IgG II Quant, Siemens Atellica IM COV2T and Euroimmun SARS-CoV-2 assay with 56 sera obtained 6-8 months after SARS-CoV-2 infection. The sensitivity of the Roche, Abbott SARS-CoV-2 IgG II Quant and Siemens antibody assays was 94.6 % (95% confidence interval (CI) 85.1-98.9 %), 98.2 % (95% CI: 90.4-99.9 %) and 100 % (95% CI: 93.6-100 %). The sensitivity of the N-based Abbott SARS-CoV-2 IgG and the glycoprotein-based Euroimmun ELISA was 48.2 % (95% CI: 34.7-62.0 %) and 83.9 % (95% CI: 71.7-92.4 %). The nucleoprotein-based Roche and the glycoprotein-based Abbott RBD and Siemens tests were more sensitive than the N-based Abbott and the Euroimmun antibody tests (p=0.0001 to p=0.039). The N-based Abbott antibody test was less sensitive 6-8 months than 4-10 weeks after SARS-CoV-2 infection (p = 0.0002). The findings show that most SARS CoV-2 antibody assays correctly identified previous infection 6-8 months after infection. The sensitivity of pan-Ig antibody tests was not reduced at 6-8 months when IgM antibodies have usually disappeared. However, one of the nucleoprotein-based antibody tests significantly lost sensitivity over time.

scholarly journals Performance Evaluation of the Siemens SARS-CoV-2 Total Antibody and IgG Antibody Test

2021 ◽  
Author(s):  
Lisa Florin ◽  
Karel Maelegheer ◽  
Wouter Vandewal ◽  
Dirk Bernard ◽  
Johan Robbrecht
Keyword(s):  
Antibody Test ◽  
Control Group ◽  
Igg Antibody ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Polymerase Chain ◽  
Kinetics Of ◽  
Antibody Tests ◽  
Positive Controls

Abstract Objective In this study, the performance of 2 commercially available SARS-CoV-2 antibody assays is evaluated. Methods The Siemens SARS-CoV-2 Total (COV2T) and IgG (COV2G) antibody tests were evaluated on a Siemens Atellica IM1300 analyzer. Imprecision was assessed with the CLSI EP15 protocol using positive controls. Ninety control group specimens were analyzed for specificity, and 175 specimens from 58 patients with polymerase chain reaction–confirmed SARS-CoV-2 were measured for the sensitivity and kinetics of the antibody response. Results Within-run and total imprecision were acceptable for both assays. Both tests showed a specificity of 100%. Sensitivity earlier in the disease state was greater for the COV2T assay than for the COV2G assay, but sensitivity >14 days after onset of symptoms approached 100% for both. For all patients, antibody titers remained above the seroconversion cutoff for all follow-up specimens. Conclusion This study shows acceptable performance for both the Siemens COV2T and COV2G test, although seroconversion occurs earlier with the COV2T test.

scholarly journals Serology characteristics of SARS-CoV-2 infection since the exposure and post symptoms onset

2020 ◽  
Author(s):  
Bin Lou ◽  
Ting-Dong Li ◽  
Shu-Fa Zheng ◽  
Ying-Ying Su ◽  
Zhi-Yong Li ◽  
...  
Keyword(s):  
Clinical Management ◽  
Early Stage ◽  
Seroconversion Rate ◽  
Public Health Practice ◽  
Antibody Test ◽  
Igg Antibody ◽  
Antibody Levels ◽  
And Control ◽  
Antibody Dynamics ◽  
Antibody Tests

AbstractBackgroundTimely diagnosis of SARS-CoV-2 infection is the prerequisite for treatment and preventive quarantine. The serology characteristics and complement diagnosis value of antibody test to RNA test needs to be demonstrated.MethodA patient cohort study was conducted at the first affiliated hospital of Zhejiang University, China. Serial plasma of COVID-19 patients and were collected and total antibody (Ab), IgM and IgG antibody against SARS-CoV-2 were detected. The antibody dynamics during the infection were described.ResultsThe seroconversion rate for Ab, IgM and IgG in COVID-19 patients was 98.8% (79/80), 93.8% (75/80) and 93.8% (75/80), respectively. The first detectible serology marker is total antibody and followed by IgM and IgG, with a median seroconversion time of 15, 18 and 20 day post exposure (d.p.e) or 9, 10 and 12 days post onset, separately. The antibody levels increased rapidly since 6 d.p.o and accompanied with the decline of viral load. For patients in the early stage of illness (0-7d.p.o),Ab showed the highest sensitivity (64.1%) compared to the IgM and IgG (33.3% for both, p<0.001). The sensitivities of Ab, IgM and IgG detection increased to 100%, 96.7% and 93.3% two weeks later, respectively.ConclusionsTypical acute antibody response is induced during the SARS-CoV-2 infection. The serology testing provides important complementation to RNA test for pathogenic specific diagnosis and helpful information to evaluate the adapted immunity status of patient. It should be strongly recommended to apply well-validated antibody tests in the clinical management and public health practice to improve the control of COVID-19 infection.Take-Home MessageAntibody responses are induced after SARS-CoV-2 infection and complement diagnosis value of antibody test to RNA test was observed. Antibody tests are critical tools in clinical management and control of SARS-CoV-2 infection and COVID-19.

scholarly journals Assessment of the Field Utility of a Rapid Point-of-Care Test for SARS-CoV-2 Antibodies in a Household Cohort

2021 ◽  
Author(s):  
Mehal Churiwal ◽  
Kelly D. Lin ◽  
Salman Khan ◽  
Srijana Chhetri ◽  
Meredith S. Muller ◽  
...  
Keyword(s):  
Cohort Study ◽  
Confidence Interval ◽  
Point Of Care ◽  
Natural Infection ◽  
Field Performance ◽  
Antibody Test ◽  
Asymptomatic Infection ◽  
Point Of Care Test ◽  
Antibody Tests ◽  
Rapid Antibody

Point-of-care (POC) tests to detect SARS-CoV-2 antibodies offer quick assessment of serostatus after natural infection or vaccination. We compared the field performance of the BioMedomics COVID-19 IgM/IgG Rapid Antibody Test against an ELISA in 303 participants enrolled in a SARS-CoV-2 household cohort study. The rapid antibody test was easily implemented with consistent interpretation across 14 users in a variety of field settings. Compared with ELISA, detection of seroconversion lagged by 5 to 10 days. However, it retained a sensitivity of 90% (160/177, 95% confidence interval [CI] 85–94%) and specificity of 100% (43/43, 95% CI 92–100%) for those tested 3 to 5 weeks after symptom onset. Sensitivity was diminished among those with asymptomatic infection (74% [14/19], 95% CI 49–91%) and early in infection (45% [29/64], 95% CI 33–58%). When used appropriately, rapid antibody tests offer a convenient way to detect symptomatic infections during convalescence.

scholarly journals Evaluation of Six Commercial Point-of-Care Tests for Diagnosis of Acute Dengue Infections: the Need for Combining NS1 Antigen and IgM/IgG Antibody Detection To Achieve Acceptable Levels of Accuracy

2011 ◽  
Vol 18 (12) ◽  
pp. 2095-2101 ◽  
Author(s):  
Stuart D. Blacksell ◽  
Richard G. Jarman ◽  
Mark S. Bailey ◽  
Ampai Tanganuchitcharnchai ◽  
Kemajittra Jenjaroen ◽  
...  
Keyword(s):  
Dengue Fever ◽  
Sensitivity And Specificity ◽  
Dengue Infection ◽  
Antibody Test ◽  
Antibody Detection ◽  
Sample Collection ◽  
Igg Antibody ◽  
Igm Antibody ◽  
Ns1 Antigen ◽  
Antibody Tests

ABSTRACTSix assays were evaluated in this study to determine their suitability for the diagnosis of acute dengue infection using samples from 259 Sri Lankan patients with acute fevers (99 confirmed dengue cases and 160 patients with other confirmed acute febrile illnesses): (i) the Merlin dengue fever IgG & IgM combo device (Merlin), (ii) the Standard Diagnostics Dengue Duo nonstructural 1 (NS1) antigen and IgG/IgM combo device (Standard Diagnostics, South Korea), (iii) the Biosynex Immunoquick dengue fever IgG and IgM (Biosynex, France) assay, (iv) the Bio-Rad NS1 antigen strip (Bio-Rad, France), (v) the Panbio Dengue Duo IgG/IgM Cassette (Inverness, Australia), and (vi) the Panbio dengue NS1 antigen strip (Inverness, Australia). The median number of days of fever prior to admission sample collection was 5 days (interquartile range, 3 to 7 days). Sensitivity and specificity of the NS1 antigen tests ranged from 49 to 59% and from 93 to 99%, respectively, and sensitivity and sensitivity of the IgM antibody test ranged from 71 to 80% and from 46 to 90%, respectively. Combining the NS1 antigen and IgM antibody results from the Standard Diagnostics Dengue Duo test gave the best compromise of sensitivity and specificity (93% and 89%, respectively) and provided the best sensitivity in patients presenting at different times after fever onset. The Merlin IgM/IgG antibody tests correctly classified 64% and 86% of the primary and secondary dengue infection cases, respectively, and the Standard Diagnostics IgM/IgG antibody tests correctly classified 71% and 83% of the primary and secondary dengue infection cases, respectively. This study provides strong evidence of the value of combining dengue antigen- and antibody-based test results in the rapid diagnostic test (RDT) format for the acute diagnosis of dengue.

scholarly journals Longitudinal Analysis of Cryptosporidium Species-Specific Immunoglobulin G Antibody Responses in Peruvian Children

2006 ◽  
Vol 13 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Jeffrey W. Priest ◽  
Caryn Bern ◽  
Lihua Xiao ◽  
Jacquelin M. Roberts ◽  
James P. Kwon ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Antibody Responses ◽  
Health Interventions ◽  
Older Children ◽  
Serum Samples ◽  
Igg Antibody ◽  
Specific Immunoglobulin ◽  
Antibody Assays ◽  
Species Specific ◽  
Antibody Levels

ABSTRACT Cryptosporidium species are ubiquitous in the environment and are frequently detected in the stools of children who live where sanitation conditions are poor. To better characterize the immune response to these parasites, we monitored immunoglobulin G (IgG) antibody levels in a cohort of children from Lima, Peru. Two new enzyme-linked immunosorbent assays based on the C. parvum (bovine, subtype IIa) Iowa strain 17-kDa and 27-kDa antigens were used to measure IgG antibody levels in longitudinal serum samples. Antibody responses were detected during infections with C. parvum, C. felis, and C. meleagridis and with four different subtypes of C. hominis. We also noted that the magnitude of the antibody response was related to the number of previous infections and that older children generally had higher levels of antibodies to the two C. parvum antigens. Antibody responses were not associated with infections with either Cyclospora sp. or Giardia sp. We believe the antibody assays will be important tools for monitoring the success of future public health interventions.

scholarly journals Use of isolated nuclei in the indirect fluorescent-antibody test for human cytomegalovirus infection: comparison with microneutralization, anticomplement, and conventional indirect fluorescent-antibody assays

1978 ◽  
Vol 7 (5) ◽  
pp. 486-489
Author(s):  
S Stagno ◽  
D W Reynolds ◽  
R J Smith
Keyword(s):  
Human Cytomegalovirus ◽  
Indirect Fluorescent Antibody Test ◽  
Fluorescent Antibody ◽  
Antibody Test ◽  
Nuclear Antigen ◽  
Indirect Fluorescent Antibody ◽  
Isolated Nuclei ◽  
Antibody Assays ◽  
Human Sera ◽  
Antibody Levels

Use of an antigen consisting of purified isolated nuclei from a mixture of human cytomegalovirus-infected and uninfected fibroblasts in a 2:1 ratio is a simple and reliable method for eliminating nonspecific fluorescence associated with the presence of Fc-immunoglobulin G receptors in the cytoplasm of infected cells. The specificity obtained with this antigen on 100 normal human sera was 99, 100, and 98% when compared with microneutralization, anticomplement immunofluorescence, and conventional indirect fluorescent-antibody assays, respectively. Also, 95% of the antibody titers obtained with the nuclear antigen had a perfect correlation with or were within a fourfold-dilution difference of the antibody levels obtained by anticomplement immunofluorescence and the conventional indirect fluorescent-antibody test.

scholarly journals Clinical characteristics and antibody response to SARS-CoV-2 spike 1 protein using the VITROS Anti-SARS-CoV-2 antibody tests in COVID-19 patients in Japan

2020 ◽  
Author(s):  
Mayu Nagura-Ikeda ◽  
Kazuo Imai ◽  
Katsumi Kubota ◽  
Sakiko Noguchi ◽  
Yutaro Kitagawa ◽  
...  
Keyword(s):  
Clinical Characteristics ◽  
Laboratory Data ◽  
Igg Antibody ◽  
Laboratory Findings ◽  
Humoral Immune ◽  
Disease Prognosis ◽  
Antibody Assays ◽  
Clinical Background ◽  
Clinical Records ◽  
Antibody Tests

Abstract Background: We evaluated clinical characteristics and the clinical utility of VITROS SARS-CoV-2 antibody tests according to COVID-19 severity in patients in Japan. Methods: We analyzed 255 serum specimens from 130 COVID-19 patients and examined clinical records and laboratory data. Presence of total (IgA, IgM, and IgG) and specific IgG antibody for the spike 1 antigen of SARS-CoV2 was determined using VITROS Anti-SARS-CoV-2 antibody tests. Findings: Overall, 98 (75.4%) and 32 (24.6%) patients had mild and severe COVID-19, respectively. On admission, 76 (58.5%) and 45 (34.6%) patients were positive for total and IgG antibody assays. Among 91 patients at discharge, 90 (98.9%) and 81 (89.0%) patients were positive for total and IgG antibody, respectively. Clinical background and laboratory findings on admission, but not the prevalence or concentration of total or IgG antibody, were associated with disease prognosis. Total and IgG antibody intensity were significantly higher in severe cases than in mild cases in serum collected after 11 days from onset, but not within 10 days. Conclusion: VITROS Anti-SARS-CoV-2 Total and IgG assays will be useful as supporting diagnostic and surveillance tools and for evaluation of humoral immune response to COVID-19. Clinical background and laboratory findings are preferable predictors of disease prognosis.

scholarly journals Distinct age-specific SARS-CoV-2 IgG decay kinetics following natural infection

2021 ◽  
Author(s):  
Calvin P Sjaarda ◽  
Emily Moslinger ◽  
Kyla Tozer ◽  
Robert I Colautti ◽  
Samira Kheitan ◽  
...  
Keyword(s):  
Natural Infection ◽  
Decay Rates ◽  
Decay Kinetics ◽  
Serum Samples ◽  
Igg Antibody ◽  
Multi Centre Study ◽  
Viral Neutralization ◽  
Antibody Levels ◽  
Over Time

Background. Antibody responses to SARS-CoV-2 can be observed as early as 14 days post- infection, but little is known about the stability of antibody levels over time. Here we evaluate the long-term stability of anti-SARS-CoV-2 IgG antibodies following infection in 402 adult donors. Methods. We performed a multi-centre study carried out at Plasma Donor Centres in the city of Heidelberg (Plasmazentrum Heidelberg, Germany) and Munich (Plasmazentrum M&uumlnchen, Germany). We present anti-S/N and anti-N IgG antibody levels in prospective serum samples collected up to 403 days post recovery from SARS-CoV-2 infected individuals. Results: The cohort includes 402 adult donors (185 female, 217 male; 17 - 68 years of age) where anti-SARS-CoV-2 IgG levels were measured in plasma samples collected between 18- and 403-days post SARS-CoV-2 infection. A linear mixed effects model demonstrated IgG decay rates that decrease over time (χ2=176.8, p<0.00001) and an interaction of time*age (χ2=10.0, p<0.005)), with those over 60+ years showing the highest baseline IgG levels and the fastest rate of IgG decay. Baseline viral neutralization assays demonstrated that serum IgG levels correlated with in vitro neutralization capacity in 91% of our cohort. Conclusion. Long-term antibody levels and age-specific antibody decay rates suggest the potential need for age-specific vaccine booster guidelines to ensure long term vaccine protection against SARS-CoV-2 infection.

scholarly journals Clinical validation of a point-of-care antibody test for COVID-19

2020 ◽  
Author(s):  
Monila Patel ◽  
Yogesh Lakhotia ◽  
Sneha Shah ◽  
Nilay Suthar ◽  
Cherry Shah ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Sensitivity And Specificity ◽  
Significant Role ◽  
Point Of Care ◽  
Antibody Test ◽  
Lateral Flow ◽  
Clinical Validation ◽  
Rt Pcr ◽  
Antibody Tests ◽  
Spike Proteins

AbstractThe objective of this study was to evaluate the performance of a lateral flow antibody test for COVID-19, approved for use in India. Although many point-of-care antibody tests are available globally, they have been subjected to limited clinical validation. This has led to suboptimal outcomes in the field, where antibody tests play a significant role in tracking the immunity of individuals and communities. In this study an antibody test, ImmunoQuick that recognizes antibodies to the Nucleocapsid and Spike proteins of SARS CoV-2 was tested in 100 symptomatic patients with a positive or negative diagnosis of COVID-19, based on RT-PCR results. The overall sensitivity of the test was found to be 86.1% (95% CI: 76.4% to 92.8%) and specificity 100% (95% confidence interval: 73.5% to 100%). The sensitivity reached a peak of 95.7% with samples taken 17 days after the onset of symptoms. Overall, the sensitivity and specificity of the test are sufficient for assessing seroprevalence.

scholarly journals Clinical characteristics and antibody response to SARS-CoV-2 spike 1 protein using VITROS Anti-SARS-CoV-2 antibody tests in COVID-19 patients in Japan

2021 ◽  
Vol 70 (4) ◽  
Author(s):  
Mayu Nagura-Ikeda ◽  
Kazuo Imai ◽  
Katsumi Kubota ◽  
Sakiko Noguchi ◽  
Yutaro Kitagawa ◽  
...  
Keyword(s):  
Antibody Response ◽  
Disease Severity ◽  
Clinical Utility ◽  
Clinical Characteristics ◽  
Igg Antibody ◽  
Laboratory Findings ◽  
Disease Prognosis ◽  
Antibody Assays ◽  
Clinical Records ◽  
Antibody Tests

Introduction. Serological tests for COVID-19 are important in providing results for surveillance and supporting diagnosis. Investigating the serological response in COVID-19 patients with different disease severity is important for assessing the clinical utility of serological assays. Gap Statement. However, few studies have investigated the clinical utility of antibody assays for COVID-19 or differences in antibody response in association with disease severity. Aim. The study aimed to evaluate the clinical characteristics and clinical utility of VITROS SARS-CoV-2 antibody tests according to COVID-19 severity in patients in Japan. Methodology. We analysed 255 serum specimens from 130 COVID-19 patients and examined clinical records and laboratory data. Presence of total (IgA, IgM, and IgG) and specific IgG antibody for the spike 1 antigen of SARS-CoV-2 was determined using VITROS Anti-SARS-CoV-2 antibody tests. Results. Overall, 98 (75.4 %) and 32 (24.6 %) patients had mild and severe COVID-19, respectively. On admission, 76 (58.5 %) and 45 (34.6 %) patients were positive for total and IgG antibody assays. Among 91 patients at discharge, 90 (98.9 %) and 81 (89.0 %) were positive for total and IgG antibody, respectively. Clinical background and laboratory findings on admission, but not the prevalence or concentration of total or IgG antibody, were associated with disease prognosis. Total and IgG antibody intensities were significantly higher in severe cases than in mild cases in serum collected >11 days after onset, but not within 10 days. Conclusion. VITROS Anti-SARS-CoV-2 total and IgG assays will be useful as supporting diagnostic and surveillance tools and for evaluation of humoral immune response to COVID-19. Optimal prediction of disease prognosis is made from considering both clinical history and laboratory findings.

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