scholarly journals Reliability of serological tests for COVID-19: Comparison of three immunochromatography test kits for SARS-CoV-2 antibodies

2020 ◽  
Author(s):  
Hidetsugu Fujigaki ◽  
Masao Takemura ◽  
Michiko Osawa ◽  
Aki Sakurai ◽  
Kentaro Nakamoto ◽  
...  
Keyword(s):  
Early Stage ◽  
Serological Test ◽  
Entire Period ◽  
Serum Samples ◽  
Igg Antibody ◽  
Serological Tests ◽  
Igm Antibody ◽  
Potential Clinical Utility ◽  
Almost All ◽  
Positive Results

AbstractBackgroundSeveral immunochromatographic serological test kits have been developed to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies, but their relative performance and potential clinical utility is unclear.MethodsThree commercially available serological test kits were evaluated using 99 serum samples collected from 29 patients diagnosed with coronavirus disease 2019 (COVID-19).ResultsThe IgM antibody-positive rates of the three serological test kits for samples taken at the early stage of the disease (0–6 days after onset) were 19.0%, 23.8%, and 19.0%, respectively. The IgM antibody-positive rates over the entire period were 21.2%, 60.6%, and 15.2%, respectively. The IgG antibody-positive rates for samples taken after 13 days of onset were 100.0%, 97.6%, and 97.6%, respectively.ConclusionThere were large differences among the results of the three test kits. Only few cases showed positive results for IgM in the early stage of disease and the IgM antibody-positive rates over the entire period were low, suggesting that the kits used in this study were unsuitable for diagnosis of COVID-19. The IgG antibody was positive in almost all samples after 13 days of onset, suggesting that it may be useful for determining infections in the recent past.

scholarly journals The loop-mediated isothermal amplification technique to determine T. gondii infection in women with spontaneous abortion

2019 ◽  
Author(s):  
Farnaz Kheirandish ◽  
Shirzad Fallahi ◽  
Hossein Mahmoudvand ◽  
Khatereh Anbari ◽  
Ali Araban ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Spontaneous Abortion ◽  
Serological Test ◽  
Isothermal Amplification ◽  
Toxoplasma Infection ◽  
Igg Antibody ◽  
Serological Tests ◽  
Loop Mediated Isothermal Amplification ◽  
Igm Antibody ◽  
Significant Difference

Abstract Background Toxoplasmosis caused by Toxoplasma gondii is well-known as one of the most widespread parasitic diseases, which has now infected nearly a third of the world's population. Among the infectious agents, T. gondii is considered as one of the main causes of spontaneous abortion (SA). The present study aimed to use the loop-mediated isothermal amplification (LAMP) technique in comparison with serological tests to determine the rate of T. gondii infection in women suffering from SA in Lorestan Province, Western Iran. Methods A total of 140 women suffering from their first spontaneous abortion and who had been referred to the Obstetrics and Gynecology Department, Asalian hospital (Khorramabad, Iran) were included in this study. The collected aborted fetal remains and blood samples (5 ml) from each patient were examined in sterilized conditions using the LAMP technique and ELISA commercial kits to determine the specific IgM and IgG anti-Toxoplasma antibodies respectively. Moreover, a questionnaire about some demographic and risk factors, such as the mother’s age, gestational age, and contact with cats was completed for each patient. Results Of the 140 women, 80 (57.1%) tested seropositive for anti-T. gondii antibodies by ELISA, 72 (51.4%) women tested seropositive for the IgG antibody, 8 (5.7%) tested seropositive for the IgM antibody. Among the 8 women who’d had their first spontaneous abortion who tested seropositive for IgM antibody by ELISA, only 5 cases (62.5%) reported positively to the LAMP test. The difference in the frequency distribution of the LAMP results for measuring the Toxoplasma infection in pregnant women under study was statistically significant (P <0.001) from the results of the serological test (ELISA). Although there was a significant difference between age and positivity in the LAMP test (P = 0.017), no significant difference was observed between positivity in the LAMP test and residence, education, job, and contact with cats. Conclusion The findings of the present investigation suggest that LAMP is a preferred method for determining Toxoplasma infection in pregnant women suffering from spontaneous abortion compared with other routine serological tests.

scholarly journals Seropositivity to canine tick-borne pathogens in a population of sick dogs in Italy

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jairo Alfonso Mendoza-Roldan ◽  
Giovanni Benelli ◽  
Marcos Antonio Bezerra-Santos ◽  
Viet-Linh Nguyen ◽  
Giuseppe Conte ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Serological Test ◽  
Control Strategies ◽  
Central Italy ◽  
Rickettsia Conorii ◽  
High Seroprevalence ◽  
The South ◽  
Serum Samples ◽  
Serological Tests ◽  
Distribution Maps

Abstract Background Canine vector-borne diseases (CVBDs) associated to ticks are among the most important health issues affecting dogs. In Italy, Ehrlichia canis, Anaplasma spp., Rickettsia conorii and Borrelia burgdorferi (s.l.) have been studied in both healthy canine populations and those clinically ill with suspected CVBDs. However, little information is currently available on the overall prevalence and distribution of these pathogens in the country. The aim of this study was to assess the prevalence and distribution of tick-borne pathogens (TBPs) in clinically suspect dogs from three Italian macro areas during a 15-year period (2006–2020). Methods A large dataset (n = 21,992) of serological test results for selected TBPs in three macro areas in Italy was analysed using a Chi-square test to evaluate the associations between the categorical factors (i.e. macro area, region, year, sex and age) and a standard logistic regression model (significance set at P = 0.05). Serological data were presented as annual and cumulative prevalence, and distribution maps of cumulative positive cases for TBPs were generated. Results Of the tested serum samples, 86.9% originated from northern (43.9%) and central (43%) Italy. The majority of the tests was requested for the diagnosis of E. canis (47%; n = 10,334), followed by Rickettsia spp. (35.1%; n = 7725), B. burgdorferi (s.l.) (11.6%; n = 2560) and Anaplasma spp. (6.2%; n = 1373). The highest serological exposure was recorded for B. burgdorferi (s.l.) (83.5%), followed by Rickettsia spp. (64.9%), Anaplasma spp. (39.8%) and E. canis (28.7%). The highest number of cumulative cases of Borrelia burgdorferi (s.l.) was recorded in samples from Tuscany, central Italy. Rickettsia spp. was more prevalent in the south and on the islands, particularly in dogs on Sicily older than 6 years, whereas Anaplasma spp. was more prevalent in the north and E. canis more prevalent in the south and on the islands. Conclusions The results of this study highlight the high seroprevalence and wide distribution of the four TBPs in dogs with clinically suspected CVBDs from the studied regions of Italy. The very high seroprevalence of B. burgdorferi (s.l.) exemplifies a limitation of this study, given the use of clinically suspect dogs and the possibility of cross-reactions when using serological tests. The present research provides updated and illustrative information on the seroprevalence and distribution of four key TBPs, and advocates for integrative control strategies for their prevention. Grapic abstract

scholarly journals Quantitative serological evaluation as a valuable tool in the COVID-19 vaccination campaign

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Davide Ferrari ◽  
Alessandra Mangia ◽  
Maria Sestina Spanò ◽  
Lucia Zaffarano ◽  
Marco Viganò ◽  
...  
Keyword(s):  
Immune Response ◽  
General Population ◽  
Serological Test ◽  
Vaccination Campaign ◽  
Age Groups ◽  
Vaccine Dose ◽  
Serum Samples ◽  
Serological Tests ◽  
Antibody Persistence ◽  
Definition Of

Abstract Objectives After exceptional research efforts, several vaccines were developed against SARS-CoV-2 which sustains the pandemic COVID-19. The Comirnaty vaccine showed high efficacy in clinical trials and was the first to be approved for its distribution to the general population. We evaluated the immune response induced by the first vaccine dose in different sex/age groups and subjects with or without naturally present anti-SARS-CoV-2 antibodies. Methods As part of an Italian multicenter project (Covidiagnostix), serum samples from 4,290 health-professionals were serologically tested the day of the first vaccination dose, and 21 days later, using two different instrumentations (Siemens-Healthineers and Roche). Results In total, 97% of samples showed the presence of specific antibodies 21 days after the vaccination dose; the percentage of non-responders increased with age in both genders. Remarkably, naturally seropositive individuals showed antibody persistence up to 11 months and an exceptionally higher vaccination response compared to subjects never infected by SARS-CoV-2. Conclusions This study highlighted the importance of the serological test i) to identify naturally SARS-CoV-2 seropositive individuals and ii) to evaluate the antibody level elicited by the first vaccination dose. Both tests, highlighted differences in the immune response, when subjects were stratified by sex and age, and between naturally seropositive and seronegative subjects. The data obtained show how serological tests could play a crucial role in the triage of the population subjected to the vaccination campaign for COVID-19. The definition of suitable instrumentation-specific thresholds is needed to correctly follow eventually acquired post-vaccination immunity in the general population.

scholarly journals Serodiagnosis of Louse-Borne Relapsing Fever with Glycerophosphodiester Phosphodiesterase (GlpQ) fromBorrelia recurrentis

2000 ◽  
Vol 38 (10) ◽  
pp. 3561-3571 ◽  
Author(s):  
Stephen F. Porcella ◽  
Sandra J. Raffel ◽  
Merry E. Schrumpf ◽  
Martin E. Schriefer ◽  
David T. Dennis ◽  
...  
Keyword(s):  
Serological Test ◽  
Geometric Mean ◽  
Eastern Africa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Relapsing Fever ◽  
Serum Samples ◽  
Serological Tests ◽  
Whole Cell ◽  
Convalescent Phase ◽  
Glycerophosphodiester Phosphodiesterase

Human louse-borne relapsing fever occurs in sporadic outbreaks in central and eastern Africa that are characterized by significant morbidity and mortality. Isolates of the causative agent,Borrelia recurrentis, were obtained from the blood of four patients during a recent epidemic of the disease in southern Sudan. TheglpQ gene, encoding glycerophosphodiester phosphodiesterase, from these isolates was sequenced and compared with the glpQ sequences obtained from other relapsing-fever spirochetes. Previously we showed that GlpQ of Borrelia hermsii is an immunogenic protein with utility as a serological test antigen for discriminating tick-borne relapsing fever from Lyme disease. In the present work, we cloned and expressed theglpQ gene from B. recurrentis and used recombinant GlpQ in serological tests. Acute- and convalescent-phase serum samples obtained from 42 patients with louse-borne relapsing fever were tested with an indirect immunofluorescence assay (IFA) and an enzyme-linked immunosorbent assay (ELISA) that used whole cells ofB. recurrentis and with immunoblotting to whole-cell lysates of the spirochete and Escherichia coli producing recombinant GlpQ. The geometric mean titers of the acute- and convalescent-phase serum samples measured by IFA were 1:83 and 1:575, respectively. The immunoblot analysis identified a high level of reactivity and seroconversion to GlpQ, and the assay was more sensitive than the whole-cell IFA and ELISA using purified, recombinant histidine-tagged GlpQ. Serum antibodies to GlpQ and other antigens persisted for 27 years in one patient. We conclude that assessment of anti-GlpQ antibodies will allow serological confirmation of louse-borne relapsing fever and determination of disease prevalence.

scholarly journals Comparison of Coombs Gel Test with ELISA and Standard Tube Agglutination Tests Used in Serological Diagnosis of Brucellosis

2020 ◽  
Vol 2 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Cigdem Akalan Kuyumcu ◽  
Serpil Erol ◽  
Rıza Adaleti ◽  
Seniha Senbayrak ◽  
Secil Deniz ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Diagnostic Tests ◽  
Serological Test ◽  
High Sensitivity ◽  
Serological Diagnosis ◽  
Control Groups ◽  
Serum Samples ◽  
Serological Tests ◽  
Reliable Test ◽  
And Control

Objective: Serological tests are the most commonly used tests in the diagnosis of brucellosis; however, each serological test has some drawbacks. In this study, we aimed to determine the value of the Brucella Coombs gel test (BCGT) in the serological diagnosis of brucellosis in comparison with Standard tube agglutination (STA) and ELISA tests. Materials and Methods: The study included 42 patients who were considered to have brucellosis as a preliminary diagnosis. BCGT, Brucella-IgM/IgG ELISA, and STA tests were performed from serum samples of the patients. The correlation of the diagnostic tests was analyzed using Cohen’s Kappa Analysis.  Results: Twenty-seven (64.2%) of 42 patients were diagnosed with brucellosis according to their medical history and clinical and serological tests. The sensitivity and specificity of BCGT to diagnose brucellosis was 96.2%, and 100%, respectively. The sensitivity and specificity for the diagnosis of brucellosis 62.9% and 100% for STA, respectively; 33.3% and 66.6% for Brucella-IgM; and 66.6% and 100% for Brucella-IgG. BCGT was significantly correlated with STA (κ= 0.590) and Brucella-IgG (κ=0.539) Conclusion: BCGT can be utilized as a simple and reliable test in the diagnosis of brucellosis with high sensitivity and specificity. Nevertheless, the sensitivity and specificity of BCGT should be demonstrated by comprehensive studies, including culture-confirmed cases and control groups.

scholarly journals The antibody response in Legionnaires' disease

1979 ◽  
Vol 83 (2) ◽  
pp. 377-381 ◽  
Author(s):  
J. Nagington ◽  
T. G. Wreghitt ◽  
J. O'H. Tobin ◽  
A. D. Macrae
Keyword(s):  
Antibody Response ◽  
Serological Test ◽  
Igg Antibodies ◽  
Immunofluorescence Technique ◽  
Igg Antibody ◽  
Recent Infection ◽  
Igm Antibody ◽  
Serotype 1 ◽  
Indirect Immunofluorescence Technique ◽  
Legionnaires Disease

summaryFrom 22 patients with Legionnaires' disease, 86 sera were examined for specific serotype 1 IgM and IgG antibodies by the indirect immunofluorescence technique.No antibody was detectable until 8 days or more from the onset of symptoms. When produced the amount was widely variable and remained detectable for periods from less than 34 days to more than 1 year.Initially IgM antibody predominated, ten patients produced only IgM in the first 21 days, six produced only IgM in the first 28 days and three did not produce IgG at any time. One patient, and possibly a second, produced only IgG antibody.Since IgM antibody was still present in one patient after a year it is important not to accept the presence of this as evidence of very recent infection.It is advisable that any type of serological test for L. pneumophila infection should detect the production of both IgM and IgG antibodies.

scholarly journals COMPARISON OF PERFORMANCE CHARACTERISTICS BETWEEN LATERAL FLOW, ELISA AND ELECTROCHEMILUMINESCENCE IMMUNOASSAYS FOR THE DETECTION OF SARS-COV-2 ANTIBODIES AMONG HEALTHCARE WORKERS

2021 ◽  
Author(s):  
M R Shincy ◽  
Vandana Govindan ◽  
H H Sudhakar ◽  
V T Venkatesha ◽  
K Padmapriya ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Healthcare Workers ◽  
Care Pathway ◽  
Point Of Care ◽  
Lateral Flow ◽  
Central Research ◽  
Serum Samples ◽  
Igg Antibody ◽  
Human Igg ◽  
Serological Tests

ABSTRACTBackgroundMedical professionals and researchers have been urging the need for wide and rapid testing of citizens in order to plan measures that can contain the spread of the virus. Antibody tests play an important role throughout the patient care pathway and are vital for the management and surveillance of the virus. Although RT-PCR is considered as the gold standard, serological tests based on antibodies are helpful for on-time detection. We performed one to one assessment of point-of-care lateral flow assay (POCTs), enzyme immunoassay (EIAs), electrochemiluminescence immunoassay (CLIA), to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibody.Materials and Methods611 healthcare workers were recruited between November and December 2020 at Central Research Laboratory, KIMS. Collected serum samples were analysed according to manufacturer’s protocol. The Standard Q IgG/IgM combo assay, Anti-SARS CoV-2 Human IgG ELISA, and the Elecsys® to measure the IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).ResultsThe kits displayed a sensitivity of 61.2%,79.5%, 91.8% and specificity of 61.7%,64.1%,80.2% for the Standard Q IgG/IgM combo assay, Anti-SARS CoV-2 Human IgG ELISA, and the Elecsys® in order.ConclusionOur results indicate high sensitivity and specificity for the Elecsys® assay compared to Anti-SARS CoV-2 Human IgG ELISA, the Standard Q IgG/IgM combo assay.

scholarly journals Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Juba, South Sudan: a population-based study

2021 ◽  
Author(s):  
Kirsten E. Wiens ◽  
Pinyi Nyimol Mawien ◽  
John Rumunu ◽  
Damien Slater ◽  
Forrest K. Jones ◽  
...  
Keyword(s):  
Test Performance ◽  
Serological Test ◽  
South Sudan ◽  
Bayesian Regression ◽  
Sub Saharan Africa ◽  
Surveillance Systems ◽  
Igg Antibody ◽  
Serological Tests ◽  
Cross Sectional ◽  
Sub Saharan

AbstractBackgroundRelatively few COVID-19 cases and deaths have been reported through much of sub-Saharan Africa, including South Sudan, although the extent of SARS-CoV-2 spread remains unclear due to weak surveillance systems and few population-representative serosurveys.MethodsWe conducted a representative household-based cross-sectional serosurvey in Juba, South Sudan. We quantified IgG antibody responses to SARS-CoV-2 spike protein receptor-binding domain and estimated seroprevalence using a Bayesian regression model accounting for test performance.ResultsWe recruited 2,214 participants from August 10 to September 11, 2020 and 22.3% had anti-SARS-CoV-2 IgG titers above levels in pre-pandemic samples. After accounting for waning antibody levels, age, and sex, we estimated that 38.5% (32.1 - 46.8) of the population had been infected with SARS-CoV-2. For each RT-PCR confirmed COVID-19 case, 104 (87-126) infections were unreported. Background antibody reactivity was higher in pre-pandemic samples from Juba compared to Boston, where the serological test was validated. The estimated proportion of the population infected ranged from 30.1% to 60.6% depending on assumptions about test performance and prevalence of clinically severe infections.ConclusionsSARS-CoV-2 has spread extensively within Juba. Validation of serological tests in sub-Saharan African populations is critical to improve our ability to use serosurveillance to understand and mitigate transmission.

scholarly journals Evaluation of Eight Serological Tests for Diagnosis of Imported Schistosomiasis

2012 ◽  
Vol 19 (6) ◽  
pp. 948-953 ◽  
Author(s):  
Hans-Friedemann Kinkel ◽  
Sabine Dittrich ◽  
Britta Bäumer ◽  
Thomas Weitzel
Keyword(s):  
Antibody Test ◽  
Parasitic Infections ◽  
Serum Samples ◽  
Serological Tests ◽  
Content Type ◽  
Commercial Kits ◽  
Few Data ◽  
Indirect Immunofluorescent ◽  
Positive Results ◽  
Immunofluorescent Antibody Test

ABSTRACTThe diagnosis of schistosomiasis in individuals from countries where the disease is not endemic is challenging, and few data are available on the accuracy of serological diagnosis in those patients. We evaluated the performance of eight serological assays, including four commercial kits, in the diagnosis of imported schistosomiasis in individuals from areas where the disease is not endemic, including six enzyme-linked immunosorbent assays using three different antigens, an indirect hemagglutination assay, and an indirect immunofluorescent-antibody test. To analyze the assays, we used a total of 141 serum samples, with 121 derived from patients with various parasitic infections (among which were 37 cases of schistosomiasis) and 20 taken from healthy volunteers. The sensitivity values for detection of schistosomiasis cases ranged from 41% to 78% and were higher forSchistosoma mansonithan forS. haematobiuminfections. Specificity values ranged from 76% to 100%; false-positive results were most frequent for samples from patients with cestode infections. By combining two or more tests, sensitivity improved markedly and specificity decreased only moderately. Serological tests are useful instruments for diagnosing imported schistosomiasis in countries where the disease is not endemic, but due to limitations in test sensitivities, we recommend the use of two or more assays in parallel.

scholarly journals Accurate Diagnosis of COVID-19 by a Novel Immunogenic Secreted SARS-CoV-2 orf8 Protein

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Xiaohui Wang ◽  
Joy-Yan Lam ◽  
Wan-Man Wong ◽  
Chun-Kit Yuen ◽  
Jian-Piao Cai ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Response ◽  
Early Stage ◽  
Serological Test ◽  
Accurate Diagnosis ◽  
Cell Culture Supernatant ◽  
Accessory Gene ◽  
Serological Tests ◽  
Asymptomatic Patients ◽  
B Cell Response

ABSTRACT An accurate diagnostic test for early severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is the key weapon to control the coronavirus disease 2019 (COVID-19) pandemic. We previously reported that the SARS-CoV-2 genome contains a unique orf8 accessory gene absent from other human-pathogenic coronaviruses. Here, we characterized the SARS-CoV-2 orf8 as a novel immunogenic secreted protein and utilized it for the accurate diagnosis of COVID-19. Extracellular orf8 protein was detected in cell culture supernatant and in sera of COVID-19 patients. In addition, orf8 was found highly immunogenic in COVID-19 patients, who showed early seropositivity for anti-orf8 IgM, IgG, and IgA. We hypothesize that orf8 secretion during SARS-CoV-2 infection facilitates early mounting of B cell response. The serological test detecting anti-orf8 IgG antibody can be used for the early and accurate diagnosis of COVID-19. IMPORTANCE Current commercially available serological tests for COVID-19 patients are detecting antibodies against SARS-CoV-2 nucleoprotein and spike glycoprotein. The antinucleoprotein and antispike antibodies can be accurately detected in patients during the mid or late stage of infection, and therefore, these assays have not been widely used for early diagnosis of COVID-19. In this study, we characterized the secretory property of a SARS-CoV-2 orf8 protein and proposed that orf8 secretion during infection facilitates early mounting of the B cell response. We demonstrated the presence of anti-orf8 antibodies in both symptomatic and asymptomatic patients during the early stage of infection, while the anti-N antibody is not detected. Our serological test detecting anti-orf8 antibodies may facilitate the development of early and accurate diagnosis for COVID-19.

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