scholarly journals Evaluating COVID-19 screening strategies based on serological tests

2020 ◽  
Author(s):  
Michela Baccini ◽  
Alessandra Mattei ◽  
Emilia Rocco ◽  
Giulia Vannucci ◽  
Fabrizia Mealli
Keyword(s):  
Reproduction Number ◽  
Serological Test ◽  
Screening Strategy ◽  
Antibody Detection ◽  
Screening Procedure ◽  
Rt Pcr ◽  
False Negatives ◽  
Serological Tests ◽  
Reliable Technique ◽  
Screening Strategies

ABSTRACTBackgroundFacing the SARS-CoV-2 epidemic requires intensive testing on the population to early identify and isolate infected subjects. Although RT-PCR is the most reliable technique to detect ongoing infections, serological tests are frequently proposed as tools in heterogeneous screening strategies. We analyze the performance of a screening strategy proposed in Tuscany (Italy), which first uses qualitative rapid tests for antibody detection, and then RT-PCR tests on the positive subjects.MethodsWe simulate the number of RT-PCR tests required by the screening strategy and the undetected ongoing infections in a pseudo-population of 500’000 subjects, under different prevalence scenarios and assuming a sensitivity of the serological test ranging from 0.50 to 0.80 (specificity=0.98). A compartmental model is used to predict the number of new infections generated by the false negatives two months after the screening, under different values of the infection reproduction number.ResultsAssuming a sensitivity equal to 0.80 and a prevalence of 0.3%, the screening procedure would require on average 11167.6 RT-PCR tests and would produce 300 false negatives, responsible after two months of a number of contagions ranging from 526 to 1132, under the optimistic scenario of a reproduction number between 0.5 to 1. Costs and false negatives increase with the prevalence.ConclusionsThe analyzed screening procedure should be avoided unless the prevalence and the rate of contagion are very low. The cost and effectiveness of the screening strategies should be evaluated in the actual context of the epidemic, accounting for the fact that it may change over time.

scholarly journals Importance of serological testing in the convalescence phase in patients with pulmonary impairment due to COVID 19 - a health care workers analysis

2021 ◽  
Author(s):  
José Rodrigues Pereira ◽  
Ilka Lopes Santoro ◽  
Maria Silvia Biagioni Santos ◽  
Andreia Padilha de Toledo ◽  
Greice Elen Copelli ◽  
...  
Keyword(s):  
Serological Test ◽  
Rt Pcr ◽  
Serological Tests ◽  
Care Workers ◽  
Pulmonary Impairment ◽  
Increased Sensitivity ◽  
Pulmonary Changes ◽  
The Subject ◽  
Convalescence Phase ◽  
The Ideal

1AbstractSince its discovery, more than 37 million people have been infected by SARS-CoV-2 with deaths around 1 million worldwide. The prevalence is not known because infected individuals may be asymptomatic. In addition, the use of specific diagnostic tests is not always conclusive, raising doubts about the etiology of the disease.The best diagnostic method and the ideal time of collection remains the subject of study. The gold standard for diagnosing COVID 19 is the RT PCR molecular test, usually using an oropharynx and nasopharynx swab. Its sensitivity is 70% and drops significantly after the second week of symptoms. Serological tests, in turn, have increased sensitivity after 14 days, and can contribute to the diagnosis when SARS-CoV-2 infection is suspected, even with negative RT PCR.Our study showed sensitivity and specificity of 100% of the serological test (ELISA method) for cases of viral pneumonia caused by the new coronavirus, suggesting that this test could assist in the diagnosis of pulmonary interstitial changes that have not yet been etiologically clarified. We found a greater immune response in men, regardless of the severity of symptoms. The greater the severity, the higher the levels of IgA and IgG, mainly found in patients with multilobar impairment and in need for oxygen. We concluded that the serological test collected around 30 days after the onset of symptoms is the best diagnostic tool in the convalescence phase, not only for epidemiological purposes, but also for the etiological clarification of pulmonary changes that have not yet been diagnosed.

scholarly journals Diagnostic Properties of Three SARS-CoV-2 Antibody Tests

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1441
Author(s):  
Suelen Basgalupp ◽  
Giovana dos Santos ◽  
Marina Bessel ◽  
Lara Garcia ◽  
Ana Carolina de Moura ◽  
...  
Keyword(s):  
Rapid Test ◽  
Epidemiological Studies ◽  
Antibody Detection ◽  
Sample Collection ◽  
Rt Pcr ◽  
Igg Antibody ◽  
Serological Tests ◽  
High Agreement ◽  
High Level ◽  
Antibody Tests

Serological assays emerged as complementary tools to RT-PCR in the diagnosis of SARS-CoV-2 as well as being needed for epidemiological studies. This study aimed to assess the performance of a rapid test (RT) compared to that of serological tests using finger prick blood samples. A total of 183 samples were evaluated, 88 of which were collected from individuals with negative RT-PCR and 95 from positive RT-PCR individuals. The diagnostic performance of RT (WONDFO®) and LUMIT (PROMEGA®) were compared to that of ELISA (EUROIMMUN®) for detecting antibodies against SARS-CoV-2 according to time from symptoms onset. The IgG antibody tests were detected in 77.4% (LUMIT), 77.9% (RT), and 80.0% (ELISA) of individuals. The detection of antibodies against SARS-CoV-2 increases in accordance with increasing time from symptoms onset. Considering only time from symptoms onset >21 days, the positivity rate ranged from 81.8 to 97.0% between the three tests. The RT and LUMIT showed high agreement with ELISA (agreement = 91.5%, k = 0.83, and agreement = 96.3%, k = 0.9, respectively) in individuals who had symptoms 15 to 21 days before sample collection. Compared to that of the ELISA assay, our results show sensitivity ranged from 95% to 100% for IgG antibody detection in individuals with symptoms onset between 15 and 21 days before sample collection. The specificity was 100% in individuals with symptoms onset >15 days before serological tests. This study shows good performance and high level of agreement of three immunoassays for the detection of SARS-CoV-2 antibodies.

scholarly journals Sero-prevalence of anti-SARS-CoV-2 Antibodies in Addis Ababa, Ethiopia

2020 ◽  
Author(s):  
Berhanu Nega Alemu ◽  
Adamu Addissie ◽  
Gemechis Mamo ◽  
Negussie Deyessa ◽  
Tamrat Abebe ◽  
...  
Keyword(s):  
Serological Test ◽  
Addis Ababa ◽  
Rapid Test ◽  
Cross Sectional Study ◽  
Rt Pcr ◽  
Serological Tests ◽  
Cross Sectional ◽  
History Of ◽  
Community Transmission ◽  
Pcr Test

AbstractBackgroundAnti-SARS-CoV-2 antibody tests are being increasingly used for sero-epidemiological purposes to provide better understanding of the extent of the infection in the community, and monitoring the progression of the COVID-19 epidemic. We conducted sero-prevalence study to estimate prior infection with with SARS-CoV-2 in Addis Ababa.MethodsA cross-sectional study was done from April 23 to 28, 2020 among 301 randomly selected residents of Addis Ababa; with no known history of contact with confirmed COVID-19 person. Interviews on socio demographic and behavioural risk factor followed by serological tests were performed for SARS-CoV-2 IgM, and IgG antibodies, using COVID-19 IgG/IgM Rapid Test Cassette. The test has sensitivity of 87·9% and specificity of 100% for lgM; and a sensitivity of 97·2% and specificity of 100% for IgG. RT-PCR test was also done on combined nasopharyngeal and oropharengeal swabs as an important public health consideration.FindingsThe unadjusted antibody-based crude SARS-CoV-2 prevalence was 7·6% and the adjusted true SARS-CoV-2 prevalence was estimated at 8·8% (95% CI 5·5%-11·6%) for the study population. Higher sero-prevalence were observed for males (9.0%), age below 50 years (8.2%), students and unemployed (15.6%), those with primary education (12.1%), smokers (7.8%), alcohol consumers (8.6%), chatt-chewers (13.6%) and shish smokers (18.8%). Seroprevalence was not significantly associated neither with socio-demographic not behavioral characteristics. According to the findings, possibly more individuals had been infected in Addis Ababa than what was being detected and reported by RT-PCR test suggestive of community transmission. The use of serological test for epidemiological estimation of the extent of SARS-CoV-2 epidemic gives a more precise estimate of magnitude which would be used for further monitoring and surveillance of the magnitude of the SARS CoV-2 infection.

scholarly journals RAPID SEROLOGICAL TESTS HAVE A ROLE IN ASYMPTOMATIC HEALTH WORKERS COVID-19 SCREENING

2020 ◽  
Author(s):  
Angelo Virgilio Paradiso ◽  
SimonaDe Summa ◽  
Nicola Silvestris ◽  
Stefania Tommasi ◽  
Antonio Tufaro ◽  
...  
Keyword(s):  
High Risk ◽  
Cancer Patients ◽  
Health Workers ◽  
Serological Test ◽  
Analytical Sensitivity ◽  
Rt Pcr ◽  
Serological Tests ◽  
Clinical Meaning ◽  
Asymptomatic Subjects

AbstractHealth workers are at high risk for SARS-CoV-2 infection and, if asymptomatic, for transmitting the virus on to fragile cancer patients. We screened 525 health workers of our Cancer Institute with rapid serological test Viva-Diag analyzingCOVID-19 associated-IgG/IgM. Six subjects (1,1%) resulted with Viva-Diag test not-negative for IgM. All 6 cases had RT-PCR SARS-CoV-2 test negative; repeating analysis ofIgG/IgM expression by CLIA assay also, 2 cases resulted IgM positive and 1 case IgG/IgM positive. This latter subject reported a contact with an infected SARS-CoV-2 person, a month earlier.In conclusion our study seems to suggest: a) a different analytical sensitivity inIgG/IgM evaluation for Viva-Diag and CLIA assays needing to be further determined; b) the ability of Viva-Diagrapid COVID-19 test to evidence health workers positive for Immunoglobulins expression. Discordant results of rapid serological tests with respect to RT-PCR stress the different clinical meaning the two assays can have, question clearly referring to further studies to optimize the utilization of rapid serological test in asymptomatic subjects at high risk for infection.

EVALUATION OF PERFORMANCE OF NINE SEROLOGICALASSAYS FOR THE DETECTION OF SARS-COV-2 ANTIBODIES.

2021 ◽  
pp. 60-62
Author(s):  
Tagajdid Mohamed Rida ◽  
Konzi Clémence ◽  
El Kochri Safae ◽  
Elannaz Hicham ◽  
Abi Rachid ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Current Knowledge ◽  
False Negative ◽  
Antibody Test ◽  
Antibody Detection ◽  
Rt Pcr ◽  
Igg Antibody ◽  
Serological Tests ◽  
Blood Samples ◽  
Test Kit

Introduction: Currently, polymerase chain reaction (PCR) based viral RNAdetection is the standard for COVID-19 diagnosis [2]. Though, RNA testing based on throat or nasopharyngeal swabs has shown a number of false-negative results. Antibody detection tests have been developed to detect specic antibodies, IgM and IgG, to SRAS-CoV-2 virus. The clinical relevance of these tests is still under evaluation and is highly related to their clinical performance. Our objective is to assess analytical performances of nine SARS-CoV-2 antibodies immunoassays. Materiel and Method: We collected 80 blood samples from PCR-conrmed COVID-19 patients diagnosed in our Virology department (20 samples collected at day 10 after the onset of symptoms, 60 collected after day 14 following the onset of symptoms) and 20 blood samples from patients SARS-CoV-2 RT-PCR negative. All sera were tested with nine SARS-CoV-2 antibodies immunoassays ARCHITECT SARS-CoV-2 IgG® (Abbott), COVID-19 VIRCLIA® IgG MONOTEST (Vircell), COVID-19 VIRCLIA® IgM+IgA MONOTEST (Vircell), COVID-19 ELISA IgG® (Vircell), COVID-19 ELISA IgM+IgA® (Vircell), Elecsys® Anti-SARS-CoV-2 (Roche), FREND® COVID-19 IgG/IgM Duo (NanoEntek), COVID-PRESTO® (AAZ) and COVID-19 (SARS-CoV-2) IgM/IgG Antibody Test Kit® (Labnovation Technologies). Results: Sensitivity of tests increases once the seroconversion to anti-SARS-CoV-2 IgG positive in most individuals occurs toward the end of week 2 post-infection. COVID-19 PRESTO had the best accuracy in our study showing 100% sensitivity after day 14 following the onset of symptoms. All of the tests had a specicity of 100%. Conclusion: Serological tests are sensitive for the latest stages of COVID-19 infection. Recommendations on using SRAS-COV-2 antibody detection tests are continuously improving based on current knowledge of host antibody responses during infection. They are of great value in cases presenting COVID-19 symptoms with negative RT-PCR.

scholarly journals Diagnosis of COVID-19 by Serology in Admitted Patients with Negative RT-PCR Assay

2021 ◽  
Author(s):  
Mitra Rezaei ◽  
Parvaneh Baghaei ◽  
Makan Sadr ◽  
Afshin Moniri ◽  
Abdolreza Babamahmoodi ◽  
...  
Keyword(s):  
Diagnostic Yield ◽  
Serological Test ◽  
False Negative ◽  
Diagnostic Methods ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Serological Tests ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain

Considering the increasing prevalence and burden of coronavirus disease 2019 (COVID-19) disease and false-negative results in routine reverse transcription-polymerase chain reaction (RT-PCR) tests, additional diagnostic methods are needed to diagnose active cases of this disease. This prospective study was conducted on patients, in whom clinical and radiological symptoms/signs were in favor of COVID-19 while their first PCR test was negative. Later on, a second RT-PCR was performed and serological evaluation was carried out and results were compared with each other. Out of 707 patients who had been referred to the hospital and were clinically and radiologically suspicious of disease, 137 patients with negative RT-PCR tests entered the study. RT-PCR assay became positive for the second time in 45 (32.8%). Anti-COVID-19 IgM and IgG antibodies were positive in 83 (60.6%) and 86 (62.8%) patients, respectively. Finally, it was determined that serological test was diagnostic in 73% of patients and the diagnostic yield of serology was significantly higher after the first week of illness (54.8% in the first week and 88% after that). Taking advantage of both serological tests and RT-PCR helps in diagnosing 83.9% of cases. Based on the present study, the serology may be useful as a complementary test and in parallel to RT-PCR assay for diagnosis of COVID-19 among admitted symptomatic cases.

Incidence of virus diseases in maize fields in the Trakya region of Turkey

2007 ◽  
Vol 87 (3) ◽  
pp. 115-122 ◽  
Author(s):  
Havva Ilbağı ◽  
Frank Rabenstein ◽  
Antje Habekuss ◽  
Frank Ordon ◽  
Ahmet Çıtır
Keyword(s):  
Mosaic Virus ◽  
Barley Yellow Dwarf Virus ◽  
Serological Test ◽  
Maize Dwarf Mosaic Virus ◽  
Rt Pcr ◽  
Virus Diseases ◽  
Serological Tests ◽  
Two Samples ◽  
Maize Plants ◽  
Yellow Dwarf Virus

Abstract A survey on maize virus diseases was conducted in the Trakya region of Turkey by examining 32 496 and 46 871 plants in 2004 and 2005, respectively. Rates of symptomatic plants were estimated at 3.7 to 63.6%, depending on locations. Biological and serological test results revealed the presence of barley yellow dwarf virus-PAV (BYDV-PAV), maize dwarf mosaic virus (MDMV), sugarcane mosaic virus (SCMV), and Johnson grass mosaic virus (JGMV). One hundred forty-two samples were collected randomly from 6492 symptomatic plants in 2004. Seventy-two out of the 142 samples were infected with MDMV, two were infected with BYDV-PAV, 19 with MDMV and BYDV-PAV, two with MDMV, BYDV-PAV and SCMV, and only one sample contained the four viruses. In 2005, 100 other leaf samples were collected randomly from 11 739 symptomatic maize plants. Serological tests revealed that 50% of the samples were infected with MDMV and SCMV; however, five showed mixed infections of two or three combinations of tested viruses. Individual MDMV, SCMV, BYDV-PAV and JGMV infections were detected in five, three, two and four samples, respectively. Presence of MDMV was confirmed by Western blot analysis and IC-RT-PCR. SCMV was also detected by IC-RT-PCR. This is the first study reporting the detection of SCMV and JGMV on maize plants in Turkey.

scholarly journals High prevalence of false positive SARS-CoV2 serology in a cohort of patients with liver autoimmune diseases

2021 ◽  
pp. 372-377
Author(s):  
Maria Giulia Cornacchia ◽  
Moris Sangineto ◽  
Rosanna Villani ◽  
Francesco Cavallone ◽  
Giuseppe Di Gioia ◽  
...  
Keyword(s):  
Autoimmune Diseases ◽  
False Positive ◽  
Serological Test ◽  
High Rate ◽  
Antibody Detection ◽  
Primary Biliary Cholangitis ◽  
Serological Response ◽  
Positive Serology ◽  
Serological Tests ◽  
False Positivity

Aim Monitoring the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) immunization in patients with autoimmune diseases is of particular concern to understand their response to the infection and to the vaccine. In fact, the immunological disorder and the immunosuppressive therapies could affect the serological response. SARS-CoV2 serological tests potentially provide this information, although they were rapidly commercialized with internal verifications. Here, we analysed the seroprevalence to SARS-CoV2 in a cohort of patients with liver autoimmune diseases. Methods From May to December 2020, a cohort of patients affected by primary biliary cholangitis (PBC), autoimmune hepatitis (AIH) and PBC/AIH overlap syndrome were screened with (reverse transcription-polymerase chain reaction) RT-PCR of nasopharyngeal swabs, rapid antigenic test and chemiluminescent serological test during routine follow-up. Results The analysis of 42 patients was carried out: 18 (42.85%) PBC, 12 (28.57%) AIH and 12 (28.57%) PBC/AIH overlap syndromes. Only 2 patients (4.76%) resulted positive to the RNA, antigen and antibody detection tests, hence affected by SARS-CoV2 infection. 14 subjects out of 40 negative cases presented a positive serology for SARS-CoV2 antibodies, hence with a false positivity in the 35% of cases without infection. Among these, 6 (42.86%) patients presented only immunoglobulin (Ig)M positivity, 6 (42.86%) patients presented positivity for only IgG and 2 (14.28%) patients were positive to both IgM and IgG. Notably, the presence of autoantibodies did not correlate with the serological false positivity, highlighting that there is no cross-reactivity with autoantibodies. The presence of polyclonal hypergammaglobulinemia did not interfere with the serological test as well. Interestingly, the patients with false positive serology showed higher levels of gamma-glutamyltransferase (GGT) and C-reactive protein (CRP). Conclusions Patients with liver autoimmune diseases present a high rate of false positive SARS-CoV2 serology. Therefore, new strategies are needed to study the serological response in this patient category.

scholarly journals Optimising triage procedures for patients with cancer needing active anticancer treatment in the COVID-19 era

ESMO Open ◽  
2020 ◽  
Vol 5 (5) ◽  
pp. e000885
Author(s):  
Grazia Arpino ◽  
Carmine De Angelis ◽  
Pietro De Placido ◽  
Erica Pietroluongo ◽  
Luigi Formisano ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Asymptomatic Patient ◽  
Serological Test ◽  
University Hospital ◽  
Serological Testing ◽  
Rt Pcr ◽  
Serological Tests ◽  
Patients With Cancer ◽  
Anticancer Treatment ◽  
Active Cancer

BackgroundImmunosuppression induced by anticancer therapy in a COVID-19-positive asymptomatic patient with cancer may have a devastating effect and, eventually, be lethal. To identify asymptomatic cases among patients receiving active cancer treatment, the Federico II University Hospital in Naples performs rapid serological tests in addition to hospital standard clinical triage for COVID-19 infection.MethodsFrom 6 to 17 April 2020, all candidates for chemotherapy, radiotherapy or target/immunotherapy, if negative at the standard clinical triage on the day scheduled for anticancer treatment, received a rapid serological test on peripheral blood for COVID-19 IgM and IgG detection. In case of COVID-19 IgM and/or IgG positivity, patients underwent a real-time PCR (RT-PCR) SARS-CoV-2 test to confirm infection, and active cancer treatment was delayed.ResultsOverall 466 patients, negative for COVID-19 symptoms, underwent serological testing in addition to standard clinical triage. The average age was 61 years (range 25–88 years). Most patients (190, 40.8%) had breast cancer, and chemotherapy with or without immunotherapy was administered in 323 (69.3%) patients. Overall 433 (92.9%) patients were IgG-negative and IgM-negative, and 33 (7.1%) were IgM-positive and/or IgG-positive. Among the latter patients, 18 (3.9%), 11 (2.4%) and 4 (0.9%) were IgM-negative/IgG-positive, IgM-positive/IgG-negative and IgM-positive/IgG-positive, respectively. All 33 patients with a positive serological test, tested negative for RT-PCR SARS-CoV-2 test. No patient in our cohort developed symptoms suggestive of active COVID-19 infection.ConclusionRapid serological testing at hospital admission failed to detect active asymptomatic COVID-19 infection. Moreover, it entailed additional economic and human resources, delayed therapy administrationand increased hospital accesses.

scholarly journals Using rapid (point-of-care) tests for COVID-19: A decision analysis comparing the expected benefit of two screening strategies

2021 ◽  
Author(s):  
Raymond H. Baillargeon ◽  
Xavier Seyer ◽  
Éricka Bernard-Bédard
Keyword(s):  
Decision Analysis ◽  
Point Of Care ◽  
Screening Strategy ◽  
Rt Pcr ◽  
Screening Strategies ◽  
Rapid Tests ◽  
Point Of Care Tests ◽  
Limited Accuracy ◽  
Rule Out

AbstractBackgroundRapid tests for COVID-19 could be used to augment the otherwise limited laboratory-based testing capacity, but there are concerns that their utility may be compromised by their limited accuracy. The objective of this article is to compare the expected benefit (EB) of two screening strategies, one with rapid tests (SwRT) and another one without rapid tests .MethodsWe performed a decision analysis, with the overall EB defined as the proportion of correctly identified individuals minus the proportion of incorrectly identified individuals. Accordingly, the SwRT strategy will be deemed a better screening strategy if its lesser EB for COVID-19 free individuals is more than compensated by its greater EB for COVID-19 individuals. Otherwise, it will not.ResultsAs expected, the EB for COVID-19 individuals was greater for the SwRT strategy, with a far superior ability to rule out the presence of COVID-19. In fact, under the scenario of interest (i.e., 8000 ID Now rapid tests in addition to 28185 lab-based RT-PCR tests), it identified almost 16% more COVID-19 individuals than the strategy. In addition, the EB for COVID-19 free individuals was the same for both strategies, with a perfect ability at ruling in the presence of COVID-19.ConclusionThe SwRT strategy identified more COVID-19 individuals and this gain was not obtained at the detriment of COVID-19 free individuals who were equally well identified by both strategies. Hence, the SwRT strategy is a better screening strategy for COVID-19. It represents an opportunity to curtail the spread of SARS-CoV-2 that we may not afford to miss with new more contagious variants becoming more and more common in Canada.

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