scholarly journals Serology in COVID-19: Comparison of Two Methods

2021 ◽  
Vol 18 (12) ◽  
pp. 6497
Author(s):  
Anna Moniuszko-Malinowska ◽  
Wojciech Jelski ◽  
Justyna Dunaj ◽  
Barbara Mroczko ◽  
Piotr Czupryna ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Nucleocapsid Protein ◽  
Spike Protein ◽  
Serological Tests ◽  
Negative Results ◽  
Positive Results ◽  
Test Result

Background: The aim of our study was to examine the performance of two assays in detecting SARS-CoV-2 antibodies. Methods: A total of 127 COVID-19 disease contacts from the Infectious Diseases Department were included. Two serological tests were used: SARS-CoV-2 IgG CMIA on the Alinity system (Abbott) and LIAISON® SARS-CoV-2 S1/S2 IgG CLIA (DiaSorin). Results: The assays exhibited a 96.85% (123/127 patients) test result agreement. In two cases, the positive results obtained by SARS-CoV-2 IgG CMIA on the Alinity system (Abbott) were negative based on the LIAISON® SARS-CoV-2 S1/S2 IgG CLIA (DiaSorin) test, and in two cases, negative results from the LIAISON® SARS-CoV-2 S1/S2 IgG CLIA (DiaSorin) test were positive with the SARS-CoV-2 IgG CMIA on the Alinity system (Abbott). Conclusions: Based on the results of our study, we conclude that in population medicine, the assessments of anti-SARS-CoV-2 antibodies after exposure to SARS-CoV-2 virus based on spike protein or nucleocapsid protein show comparable effectiveness.

scholarly journals False Positive Results in SARS-CoV-2 Serological Tests for Samples From Patients With Chronic Inflammatory Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Nastya Kharlamova ◽  
Nicky Dunn ◽  
Sahl K. Bedri ◽  
Svante Jerling ◽  
Malin Almgren ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
False Positive ◽  
Inflammatory Diseases ◽  
Serological Tests ◽  
Chronic Inflammatory Diseases ◽  
Negative Results ◽  
False Positive Signal ◽  
Lateral Flow Assays ◽  
Positive Results ◽  
Multiplex Bead

Patients with chronic inflammatory diseases are often treated with immunosuppressants and therefore are of particular concern during the SARS-CoV-2 pandemic. Serological tests will improve our understanding of the infection and immunity in this population, unless they tests give false positive results. The aim of this study was to evaluate the specificity of SARS-Cov-2 serological assays using samples from patients with chronic inflammatory diseases collected prior to April 2019, thus defined as negative. Samples from patients with multiple sclerosis (MS, n=10), rheumatoid arthritis (RA, n=47) with or without rheumatoid factor (RF) and/or anti-cyclic citrullinated peptide antibodies (anti-CCP2) and systemic lupus erythematosus (SLE, n=10) with or without RF, were analyzed for SARS-CoV-2 antibodies using 17 commercially available lateral flow assays (LFA), two ELISA kits and one in-house developed IgG multiplex bead-based assay. Six LFA and the in-house validated IgG assay correctly produced negative results for all samples. However, the majority of assays (n=13), gave false positive signal for samples from patients with RA and SLE. This was most notable in samples from RF positive RA patients. No false positive samples were detected in any assay using samples from patients with MS. Poor specificity of commercial serological assays could possibly be, at least partly, due to interfering antibodies in samples from patients with chronic inflammatory diseases. For these patients, the risk of false positivity should be considered when interpreting results of the SARS-CoV-2 serological assays.

scholarly journals Identification of etiological agents of selected bacterial and viral infections based on serological tests

2018 ◽  
Vol 72 ◽  
pp. 1162-1178
Author(s):  
Aleksandra Lewandowicz-Uszyńska ◽  
Piotr Naporowski ◽  
Gerard Pasternak ◽  
Danuta Witkowska
Keyword(s):  
False Positive ◽  
Cellular Response ◽  
Bacterial Infections ◽  
Viral Infections ◽  
False Negative ◽  
Main Role ◽  
Serological Tests ◽  
Negative Results ◽  
False Negative Results ◽  
Positive Results

The human immune system’s response to infection is closely related with the type of pathogen. First, a rapid, metabolically inexpensive and non-specific innate immunity is induced, then a specific acquired immunity is activated. In bacterial infections caused by intracellular pathogens, the main role is played by cellular response. In infections caused by bacterial extracellular pathogens, a crucial role is played by antibodies. The clinical symptoms of bacterial and viral infections very often are similar, which is why diagnosing them based only on medical history and physical examination is insufficient. To identify the etiological factors of infections differentiating media, biochemical tests, molecular methods and serological tests are used. The detection of microorganisms or their genetic material can be performed within a short time after the occurrence of an infection. The detection of antibodies is possible only in the appropriate time called the serological window. In a serological diagnostic of infections there are problems with an appropriate interpretation of obtained results. Cross-reactivity can give false positive results for the diagnosis of Chlamydophila pneumonia infection. The problem with the detection of Borrelia burgdorferi infection can be caused by a simultaneous coinfection with different spirochetes, syphilis, mononucleosis or HIV. In serological diagnostics of bacterial infections, the administration of antibiotics to patients before taking serum samples can be responsible for false negative results. Another reason for such results can be a weak humoral response in infected patients. In viral infections, false positive results can be caused by a coinfection of different viruses, especially from the same family or by bacterial or protozoal coinfections or by autoimmune diseases. False-negative results in viral infections often are caused by the early phase of an infection. To properly recognize an etiological factor of infection it is necessary to use an appropriate method, precision of test and collect samples at the appropriate time.

scholarly journals Demonstrating the presence of Ehrlichia canis DNA from different tissues of dogs with suspected subclinical ehrlichiosis

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Carlos A. Rodríguez-Alarcón ◽  
Diana M. Beristain-Ruiz ◽  
Angélica Olivares-Muñoz ◽  
Andrés Quezada-Casasola ◽  
Federico Pérez-Casio ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Lymph Node ◽  
Cross Reactivity ◽  
Ehrlichia Canis ◽  
Serological Tests ◽  
Blood Samples ◽  
Negative Results ◽  
Target Organs ◽  
Polymerase Chain ◽  
Positive Results

Abstract Background Nowadays, Ehrlichia canis receives increasing attention because of its great morbidity and mortality in animals. Dogs in the subclinical and chronic phases can be asymptomatic, and serological tests show cross-reactivity and fail to differentiate between current and past infections. Moreover, there could be low parasitaemia, and E. canis might be found only in target organs, hence causing results to be negative by polymerase chain reaction (PCR) on blood samples. Methods We evaluated by PCR the prevalence of E. canis in blood, liver, spleen, lymph node and bone marrow samples of 59 recently euthanised dogs that had ticks but were clinically healthy. Results In total, 52.55% of the blood PCRs for E. canis were negative, yet 61.30% yielded positive results from tissue biopsies and were as follows: 63.15% from bone marrow; 52.63% from liver; 47.36% from spleen; and 15.78% from lymph node. In addition, 33% had infection in three tissues (spleen, liver and bone marrow). Conclusions Our results show the prevalence of E. canis from tissues of dogs that were negative by blood PCR. Ehrlichia canis DNA in tissue was 30% lower in dogs that tested negative in PCR of blood samples compared to those that were positive. However, it must be taken into account that some dogs with negative results were positive for E. canis in other tissues.

scholarly journals SARS-CoV-2 serological tests can generate false positive results for samples from patients with chronic inflammatory diseases

2020 ◽  
Author(s):  
Nastya Kharlamova ◽  
Nicky Dunn ◽  
Sahl K Bedri ◽  
Svante Jerling ◽  
Malin Almgren ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
False Positive ◽  
Inflammatory Diseases ◽  
Serological Tests ◽  
Chronic Inflammatory Diseases ◽  
Negative Results ◽  
False Positive Signal ◽  
Lateral Flow Assays ◽  
Positive Results ◽  
Multiplex Bead

AbstractObjectivesPatients with chronic inflammatory diseases are often treated with immunosuppressants and therefore are of particular concern during the SARS-CoV-2 pandemic. Serological tests will improve our understanding of the infection and immunity in this population, unless the tests give false positive results. The aim of this study was to evaluate the specificity of SARS-Cov-2 serological assays with samples from patients with chronic inflammatory diseases collected before April 2019, thus defined as negative.MethodsSamples from patients with multiple sclerosis (MS, n=10), rheumatoid arthritis (RA, n=47) with or without rheumatoid factor (RF) and/or anti-cyclic citrullinated peptide antibodies (anti-CCP2) and RF +/- systemic lupus erythematosus (SLE, n=10), were tested with 17 commercially available lateral flow assays (LFA), two ELISA kits and one in-house developed multiplex bead-based assay.ResultsSix LFA and the in-house IgG assay gave the correct negative results for all samples. However, the majority of assays (n=13), gave false positive signal with samples from patients with RA and SLE. This was most notable in RF positive RA samples. MS samples did not give any false positive in any of the assays.ConclusionThe majority of the verified serological assays were sensitive to interfering antibodies in samples from patients with chronic inflammatory diseases and therefore may have poor specificity in this context. For these patients, the risk of false positivity should be considered when interpreting results of the SARS-CoV-2 serological assays.

scholarly journals Serology in COVID-19 – Comparison of Two Methods

2020 ◽  
Author(s):  
Anna Moniuszko-Malinowska ◽  
Wojciech Jelski ◽  
Justyna Dunaj ◽  
Barbara Mroczko ◽  
Piotr Czupryna ◽  
...  
Keyword(s):  
Serological Tests ◽  
S Protein ◽  
Negative Results ◽  
The Difference ◽  
Positive Results

Abstract The aim of our study was to investigate the difference in the anti-SARS-CoV-2 antibodies assessment with two various assays. 127 patients exposed to SARS-CoV-2 were included. Two serological tests were used: SARS-CoV-2 IgG CMIA on the Alinity system (ABBOTT) and LIAISON® SARS-CoV-2 S1/S2 IgG CLIA (DiaSorin). Both assays exhibited 96.85% (123/127 patients) overall compatibility. In 2 cases the positive results in N-based test, were negative in S-based test, and in 2 cases negative results in S-based test were positive in N-based test. Based on the results of our study we concluded that the assessment of anti-SARS-CoV-2 antibodies against N and S protein in population medicine shows comparable usefulness of both tests.

scholarly journals Immunoblot Assay Using Recombinant Antigens as a Supplemental Test To Confirm the Presence of Antibodies to Trypanosoma cruzi

2007 ◽  
Vol 14 (4) ◽  
pp. 355-361 ◽  
Author(s):  
Kevin Y. Cheng ◽  
Chi-Deu Chang ◽  
Vince A. Salbilla ◽  
Louis V. Kirchhoff ◽  
David A. Leiby ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
False Positive ◽  
Test Results ◽  
Serological Tests ◽  
Assay Sensitivity ◽  
Immunoblot Assay ◽  
Recombinant Antigens ◽  
Persistent Problem ◽  
Negative Results ◽  
Positive Results

ABSTRACT The diagnosis of chronic Chagas' disease is generally made by detecting antibodies to Trypanosoma cruzi. Most conventional serological tests are based on lysates of whole parasites or semipurified antigen fractions from T. cruzi epimastigotes grown in culture. The occurrence of inconclusive and false-positive results has been a persistent problem with the conventional assays, and there is no universally accepted gold standard for confirmation of positive test results. We describe here an immunoblot assay for detecting antibodies to T. cruzi in which four chimeric recombinant antigens (rAgs), designated FP3, FP6, FP10, and TcF, are used as target antigens. Each of these rAgs is composed of several antigenically distinct regions and includes repetitive as well as nonrepetitive sequences. Each rAg is coated as a discrete line on a nitrocellulose strip. Assay sensitivity was assessed by testing 345 specimens known to be positive for antibodies to T. cruzi. All 345 of these samples showed two to four reactive test bands in addition to the three on-board control bands that are on each strip. Assay specificity was determined by testing 500 specimens from random U.S. blood donors, all of which gave negative results. Based on the results obtained in this study, we propose the following scheme for interpretation of test results: (i) no bands or a single test band = a negative result; (ii) two or more test bands with at least one band showing intensity of 1+ or higher = a positive result; and (iii) multiple faint test bands (±) = indeterminate result. Based on this scheme, the prototype immunoblot assay showed sensitivity of 100% (n = 345) and specificity of 100% (n = 500). Additionally, all 269 potentially cross-reacting and T. cruzi antibody-negative specimens tested negative in our immunoblot assay. The rAg-based immunoblot assay has potential as a supplemental test for confirming the presence of antibodies to T. cruzi in blood specimens and for identifying false-positive results obtained with other assays.

scholarly journals Centrifugation may eliminate false-positive leucocyte esterase strip test results caused by inflammatory arthritis in the diagnosis of knee infection

2020 ◽  
Vol 9 (5) ◽  
pp. 236-241
Author(s):  
Rui Li ◽  
Chi Wang ◽  
Xiao-Jian Ji ◽  
Qing-Yuan Zheng ◽  
Xiang Li ◽  
...  
Keyword(s):  
False Positive ◽  
Inflammatory Arthritis ◽  
Test Results ◽  
Knee Infection ◽  
Negative Results ◽  
Before And After ◽  
Strip Test ◽  
Positive Results ◽  
Test Result ◽  
Colour Chart

Aims The purpose of this study was to validate our hypothesis that centrifugation may eliminate false-positive leucocyte esterase (LE) strip test results caused by autoimmune diseases in the diagnosis of knee infection. Methods Between January 2016 and May 2019, 83 cases, including 33 cases of septic arthritis and 50 cases of aseptic arthritis, were enrolled in this study. To further validate our hypothesis, another 34 cases of inflammatory arthritis from the Department of Rheumatology of our institution were also included. After aspiration, one drop of synovial fluid was applied to LE strips before and after centrifugation. The results were recorded after approximately three minutes according to the different colour grades on the colour chart. The differences of LE results between each cohort were analyzed. Results Before centrifugation, 46% (23/50) of the LE strip tests in the aseptic arthritis group were false-positives. Most of the false-positive results were due to inflammatory arthritis; after centrifugation, 78.3% (18/23) of the tests yielded negative results. Similar results were observed in cases from the Department of Rheumatology. The sensitivity of the centrifuged LE strip test was 0.818 (0.639 to 0.924), which is still an acceptable level compared with the uncentrifuged results, which yielded a sensitivity of 0.909 (0.745 to 0.976). However, the specificity was increased from 0.540 (0.395 to 0.679) to 0.900 (0.774 to 0.963) after centrifugation. Conclusion Although inflammatory arthritis can yield a false-positive LE strip test result in the diagnosis of knee infection, centrifugation may eliminate these false-positive results. Cite this article: Bone Joint Res. 2020;9(5):236–241.

Attitudes and Perceptions About Disclosing HIV and Syphilis Results Using Smarttest, a Smartphone App Dedicated to Self- and Partner Testing

2021 ◽  
Vol 33 (3) ◽  
pp. 234-248
Author(s):  
Bryan A. Kutner ◽  
Anthony T. Pho ◽  
Javier López-Rios ◽  
Cody Lentz ◽  
Curtis Dolezal ◽  
...  
Keyword(s):  
Partner Notification ◽  
Linkage To Care ◽  
Sexual Partners ◽  
Smartphone App ◽  
Test Results ◽  
Negative Results ◽  
Partner Testing ◽  
Attitudes And Perceptions ◽  
Positive Results ◽  
Test Result

We explored interest in disclosing test results through a smartphone app dedicated to self- and partner testing for HIV/syphilis. Fifty-nine cisgender men and transgender women each participated in an in-person survey and interview. We examined their interests in sharing test results by audience (e.g., partners, physicians) and by positive versus negative test result. Participants wanted the ability to share results, with notable interest in disclosing negative results to sexual partners and on social media and forwarding positive results to physicians. Participants envisioned smartphone sharing as a means to normalize testing, to notify partners of results, and to expedite linkage to care. Some questioned the authenticity of results shared by smartphone, while others voiced optimism that a personalized, authenticated app could ensure the security and veracity of results. Smartphone testing apps for HIV/syphilis may facilitate disclosure, partner notification, and linkage to care, but need to address concerns about the security and veracity of results.

scholarly journals Evaluation of rapid, cassette immunochromatographic tests in the serological diagnosis of COVID-19

2021 ◽  
pp. 25-37
Author(s):  
Waldemar Rastawicki ◽  
Klaudia Płaza ◽  
Adam Pietrusiński
Keyword(s):  
Low Cost ◽  
Lateral Flow ◽  
Serological Diagnosis ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Serological Tests ◽  
Negative Results ◽  
Lateral Flow Assays ◽  
Low Sensitivity ◽  
Positive Results

Introduction: Lateral flow assays (LFIA) are the technology behind low-cost, simple, rapid and portable detection devices popular in biomedicine. Lately, they are very common used in serodiagnosis of SARS-CoV-2 infections. The aim of the presented study was to assess the usefulness of selected LFIA in serological diagnosis of COVID-19. Methods: The usefulness of seven lateral flow assays in the serodiagnosis of COVID-19 was evaluated (VAZYME, DIAGNOSIS, PCL, INGEZIM, BIOSENSOR, ACCU-TELL, NOVAtest). The study used 107 serum samples obtained from 74 individuals with current SARS-CoV-2 infection confirmed by RT-PCR. The ELISA-IgG (Euroimmun) was used as the reference assay for sensitivity and specificity testing. Results: The highest percentage of positive results was obtained when searching for IgG antibodies with the NOVAtest (40.6%) and DIAGNOSIS (39.2%) sets and the lowest detection for the PCL set - 25.5%. In the case of searching for IgM antibodies in all sets, significantly lower percentages of positive results compared to the IgG class were recorded. In general, all lateral flow assays showed low sensitivity in relation to the Euroimmun ELISA-IgG. The DIAGNOSIS kit (64.5%) was characterized by the highest sensitivity, and the PCL kit was the lowest (38.7%). On the other hand, the specificity of all kits was very high, almost 100% in almost all cases. Conclusions: Lateral flow assays due to their low sensitivity are not suitable for quick diagnosis of the current SARS-CoV-2 infections and cannot be an alternative to genetic or even antigen tests. They may be used only to retrospectively test the presence of IgG antibodies. However, a negative results of LFIA in suspected disease or after vaccination should be confirmed by more sensitive serological tests.

Improving the Sensitivity and the Specificity of HLA-B27 Typing by Replacing Serological Tests with a TaqMan-PCR Assay

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4720-4720
Author(s):  
Xiaoduan Weng ◽  
Louise Robin ◽  
Marie-lise Audet ◽  
Linda Hébert ◽  
Ginette Lapointe ◽  
...  
Keyword(s):  
Detection System ◽  
Cross Reactivity ◽  
Hla B27 ◽  
Serological Tests ◽  
Dna Assay ◽  
Negative Results ◽  
Flow Cytometric ◽  
Antigen Assay ◽  
Taqman Pcr ◽  
Positive Results

Abstract HLA-B27 is a strong diagnostic biomarker as it is found in 90– 95% of ankylosing spondylitis. Routinely, the false-positive results generated by cross-reactivity of HLA-B27 monoclonal antibodies (mAbs) with some other type of HLA-B antigens are problematic. The present study aims at improving the sensitivity and specificity of typing for HLA-B27 by using a more accurate DNA assay. A real time sequence specific primer polymerase chain reaction (PCR-SSP) is performed by using MGB TaqMan oligoprobe and an ABI PRISM™ 7500 sequence detection system. The TaqMan PCR-SSP assay is compared with Immunophenotyping by flow cytometric antigen assay (BD HLA-B27-Kit, clone GS145.2). The results are finally confirmed by sequencing (ABI PRISM ® 3100). As summarised in the table, three methods are identical for clearly positive and negative results. There is 90% concordance for borderline negative results obtained by immunophenotyping with TaqMan PCR-SSC and/or sequencing. However, only 15.4% of borderline positives obtained by immunophenotyping are confirmed as true HLA-B27 positives by sequencing as well as TaqMan PCR-SSC. TaqMan PCR-SSP DNA assay completely correlates with sequencing (gold standard) with 100% PPV and NPV, compared to a PPV of 15% and a NPV of 98% for borderline results by immunophenotyping. Conclusion: when compared with flow cytometric antigen assay, typing HLA-B27 by TaqMan PCR-SSP clearly demonstrates an advantage to better establish the genotype of the patient. Specifically, there is a marked difference for ambitious positive results from immunophenotyping. Moreover, compared to immunophenotyping, there is no need of fresh samples, can test a larger number of samples concomitantly, and reduces technical time as well as cost. N = 52 Immunophenotyping TaqMan PCR-SSP Sequencing Immuno vs Sequencing TaqMan PCR-SSP vs Sequencing Positive 11 11 11 100% 100% Negative 17 17 17 100% 100% Positive (borderline by Immunophenotyping) 13 2 2 15% 100% Negative (borderline ) by Immunophenotyping) 10 9 9 98% 100%

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