SARS-CoV-2 Serology Testing in an Asymptomatic, At-Risk Population: Methods, Results, Pitfalls

The primary aim of this study was to determine the seroprevalence of SARS-CoV-2 antibodies in a population of pediatric healthcare workers (HCWs). This study was conducted 14 May–13 July 2020. Study participants included pediatric HCWs at a pediatric hospital with either direct patient contact or close proximity to patient-care areas. SARS-CoV-2 antibodies were assessed via the Wytcote Superbio SARS-CoV-2 IgM/IgG Antibody Fast Detection Kit and the Abbott Architect SARS-CoV-2 IgG assay. Participants underwent RT-PCR testing upon entry to the study and following rapid IgM+/IgG+ results; respiratory panel PCR (RP-PCR) was performed following IgM+ results. A total of 57 of 289 (19.7%) of participants demonstrated positive serology as assessed by the Wytcote rapid kit (12 on Day 1 and 45 throughout the study). However, only one of these participants demonstrated IgG+ serology via the Abbott assay. Two participants tested SARS-CoV-2+ via RT-PCR testing. One individual was adenovirus+ and enterovirus/rhinovirus+. In our study population, we observed a seroprevalence of SARS-CoV-2 antibodies of 0.35%. The lack of concordance between antibody tests suggests that the Wytcote rapid test kit may not be of use as a screening tool. However, the feasibility of the overall process indicates that a similar methodology may have potential for future epidemiologic surveillance.

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Evaluating ELISA, Immunofluorescence, and Lateral Flow Assay for SARS-CoV-2 Serologic Assays

Frontiers in Microbiology ◽

10.3389/fmicb.2020.597529 ◽

2020 ◽

Vol 11 ◽

Author(s):

Moïse Michel ◽

Amar Bouam ◽

Sophie Edouard ◽

Florence Fenollar ◽

Fabrizio Di Pinto ◽

...

Keyword(s):

Rapid Test ◽

Antibody Test ◽

Immunofluorescence Assay ◽

Lateral Flow ◽

Antibody Detection ◽

Rt Pcr ◽

Igg Antibody ◽

Reliable Determination ◽

Test Kit ◽

Serological Status

BackgroundThe SARS-CoV-2 outbreak has emerged at the end of 2019. Aside from the detection of viral genome with specific RT-PCR, there is a growing need for reliable determination of the serological status. We aimed at evaluating five SARS-CoV-2 serology assays.MethodsAn in-house immunofluorescence assay (IFA), two ELISA kits (EUROIMMUN® ELISA SARS-CoV-2 IgG and NovaLisa® SARS-CoV-2 IgG and IgM) and two lateral flow assays (T-Tek® SARS-CoV-2 IgG/IgM Antibody Test Kit and Sure Bio-tech® SARS-CoV-2 IgM/IgG Antibody Rapid Test) were compared on 40 serums from RT-PCR-confirmed SARS-CoV-2 infected patients and 10 SARS-CoV-2 RT-PCR negative subjects as controls.ResultsControl subjects tested negative for SARS-CoV-2 antibodies with all five systems. Estimated sensitivities varied from 35.5 to 71.0% for IgG detection and from 19.4 to 64.5% for IgM detection. For IgG, in-house IFA, EuroImmun, T-Tek and NovaLisa displayed 50–72.5% agreement with other systems except IFA vs EuroImmun and T-Tek vs NovaLisa. Intermethod agreement for IgM determination was between 30 and 72.5%.DiscussionThe overall intermethod agreement was moderate. This inconsistency could be explained by the diversity of assay methods, antigens used and immunoglobulin isotype tested. Estimated sensitivities were low, highlighting the limited value of antibody detection in CoVID-19.ConclusionComparison of five systems for SARS-CoV-2 IgG and IgM antibodies showed limited sensitivity and overall concordance. The place and indications of serological status assessment with currently available tools in the CoVID-19 pandemic need further evaluations.

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Incorporating false negative tests in epidemiological models for SARS-CoV-2 transmission and reconciling with seroprevalence estimates

Scientific Reports ◽

10.1038/s41598-021-89127-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Rupam Bhattacharyya ◽

Ritoban Kundu ◽

Ritwik Bhaduri ◽

Debashree Ray ◽

Lauren J. Beesley ◽

...

Keyword(s):

False Negative ◽

Population Based ◽

Training Data ◽

Epidemiological Models ◽

Rt Pcr ◽

Antibody Prevalence ◽

Igg Antibody ◽

False Negatives ◽

Seir Model ◽

Study Population

AbstractSusceptible-Exposed-Infected-Removed (SEIR)-type epidemiologic models, modeling unascertained infections latently, can predict unreported cases and deaths assuming perfect testing. We apply a method we developed to account for the high false negative rates of diagnostic RT-PCR tests for detecting an active SARS-CoV-2 infection in a classic SEIR model. The number of unascertained cases and false negatives being unobservable in a real study, population-based serosurveys can help validate model projections. Applying our method to training data from Delhi, India, during March 15–June 30, 2020, we estimate the underreporting factor for cases at 34–53 (deaths: 8–13) on July 10, 2020, largely consistent with the findings of the first round of serosurveys for Delhi (done during June 27–July 10, 2020) with an estimated 22.86% IgG antibody prevalence, yielding estimated underreporting factors of 30–42 for cases. Together, these imply approximately 96–98% cases in Delhi remained unreported (July 10, 2020). Updated calculations using training data during March 15-December 31, 2020 yield estimated underreporting factor for cases at 13–22 (deaths: 3–7) on January 23, 2021, which are again consistent with the latest (fifth) round of serosurveys for Delhi (done during January 15–23, 2021) with an estimated 56.13% IgG antibody prevalence, yielding an estimated range for the underreporting factor for cases at 17–21. Together, these updated estimates imply approximately 92–96% cases in Delhi remained unreported (January 23, 2021). Such model-based estimates, updated with latest data, provide a viable alternative to repeated resource-intensive serosurveys for tracking unreported cases and deaths and gauging the true extent of the pandemic.

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Avian influenza and Newcastle disease virusindead chickens in markets in Dhaka, Bangladesh in 2011-2012

Bangladesh Veterinarian ◽

10.3329/bvet.v33i1.33308 ◽

2017 ◽

Vol 33 (1) ◽

pp. 8-15

Author(s):

LR Barman ◽

RD Sarker ◽

BC Das ◽

EH Chowdhury ◽

PM Das ◽

...

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Newcastle Disease ◽

Rapid Test ◽

Type A ◽

Antigen Test ◽

Rt Pcr ◽

Test Kit ◽

Live Bird

A virological survey for avian influenza (AI) and Newcastle disease (ND) was conducted in two selected live bird markets (LBMs), namely Kaptan Bazar and Karwan Bazar in Dhaka city, Bangladesh from August 2011 to July 2012. A total of 513 dead chickens were collected. An immune-chromatographic rapid antigen test for Type A influenza virus and both conventional and real time RT-PCR were used for the detection and characterization of AI and ND viruses. All carcasses were first screened by the rapid antigen test kit and 93 were positive for Type A influenza virus. RT-PCR on a representative number of rapid antigen test positive samples (n = 24) confirmed the presence of Type A influenza virus and mostly H5 influenza virus (22 out of 24 tested samples). Influenza rapid test negative samples (n = 420) were subjected to routine necropsy. Heat stress, suffocation and physical injury were the most common cause of mortality (163 cases), followed by ND, suspected to be the cause of 85 deaths. On molecular investigation of these 85 samples, the presence of ND virus was confirmed in 59 and AI virus in 6; 15 were negative for both ND and AI viruses and 5 were unsuitable for investigation. Among the 59 ND confirmed cases 18 also contained AI virus. In summary, out of 513 carcasses 117 (22.81%) contained AI virus and 59 (11.50%) contained ND virus. Eighteen (3.51%) carcasses contained both AI and ND viruses. The findings suggest that both AI and ND should be considered as major threats to the poultry industry.Bangl. vet. 2016. Vol. 33, No. 1, 8-15

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Diagnostic Properties of Three SARS-CoV-2 Antibody Tests

Diagnostics ◽

10.3390/diagnostics11081441 ◽

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.

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Validation of rapid antibody (IgG-IgM) test kit for SARS COV-2 infection in Qatar

Journal of Public Health Research ◽

10.4081/jphr.2021.2421 ◽

2021 ◽

Author(s):

Jesha Mundodan ◽

Samina Hasnain ◽

Hayat Khogali ◽

Soha Shawqi Al Bayat ◽

Dina Ali ◽

...

Keyword(s):

Predictive Value ◽

Local Population ◽

Rapid Test ◽

Antibody Test ◽

Molecular Testing ◽

Rt Pcr ◽

Test Kit ◽

Asymptomatic Individuals ◽

Sensitivity Specificity ◽

Rapid Antibody

Background: In response to the growing coronavirus disease 2019 (COVID-19) pandemic and the shortage of laboratory based molecular testing capacity and reagents, multiple diagnostic test manufacturers have developed rapid and easy to use devices to facilitate testing outside laboratory settings. These kits are either based on detection of proteins from SARS-CoV-2 virus or detection of antigen or human antibodies generated in response to the infection. However, it is important to understand their performance characteristics and they must be validated in the local population setting.Design and Methods: The objective is to assess the validity of the rapid test for IgG and IgM immunoglobulins compared to the current gold standard reverse transcription polymerase chain reaction (RT-PCR) test. A total of 16951 asymptomatic individuals were tested by the Ministry of Public Health track-and-trace team using both rapid immunodiagnostic test and RT-PCR as part of screening across various random settings with potential risk of community interaction prior to gradual lifting of restrictions in Qatar. Rapid test was considered to be posiive if both IgG and IgM are positive, while only IgG/IgM positive was considered as rapid test negative. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.Results: The sensitivity of rapid test kit was found to be 0.9%, whereas the specificity was found to be 97.8%. the PPV was found to be 0.3% whereas the NPV was found to be 99.4%.Conclusion: Based on the outcome and results of the study, it appears that the sensitivity and PPV of the rapid antibody test are low. As such, this test is not recommended for use to assist in taking clinic-based decisions or decisions related to quarantine/isolation.

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Should IgM/IgG rapid test kit be used in the diagnosis of COVID-19?

Acta Medica Philippina ◽

10.47895/amp.v54i0.1558 ◽

2020 ◽

Vol 54 ◽

Author(s):

Aldrich Ivan Lois D. Burog ◽

Clarence Pio Rey C. Yacapin ◽

Renee Rose O. Maglente ◽

Anna Angelica Macalalad-Josue ◽

Elenore Judy B. Uy ◽

...

Keyword(s):

Direct Detection ◽

Rapid Test ◽

Definitive Diagnosis ◽

Rapid Review ◽

Current Evidence ◽

Rt Pcr ◽

Qualitative Detection ◽

Test Kit ◽

Polymerase Chain ◽

Antibody Tests

KEY FINDINGS Current evidence does NOT support use of IgM/IgG rapid test kits for the definitive diagnosis of COVID-19 in currently symptomatic patients. • The present standard for diagnosis of COVID-19 is through qualitative detection of COVID-19 virus nucleic acid via reverse transcription polymerase chain reaction (RT-PCR). • Due to long turnaround times and complicated logistical operations, a rapid and simple field test alternative is needed to diagnose and screen patients. • An alternative to the direct detection and measurement of viral load (RT-PCR) is the qualitative detection of specific antibodies to COVID-19. ELISA (discussed in a separate rapid review) and lateral flow immunoassay (LFIA) IgM/IgG rapid test kits are two currently available, qualitative, antibody tests for COVID-19. • Two low quality clinical trials showed that there is insufficient evidence to support the use of IgM/IgG rapid test kits for the definitive diagnosis of COVID-19. Diagnostic accuracy varies greatly depending on the timing of the test. The test performed very poorly during the early phase of the disease (i.e., less than eight days from onset of symptoms). • Existing guidelines do not recommend serologic antibody tests for the diagnosis of COVID-19 in currently symptomatic patients.

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Development of rapid immunochromatographic strip test for the detection of porcine epidemic diarrhoea virus

Veterinary Record ◽

10.1136/vr.103959 ◽

2017 ◽

Vol 181 (22) ◽

pp. 596-601 ◽

Cited By ~ 7

Author(s):

Kwang-Soo Lyoo ◽

Minjoo Yeom ◽

Jungho Kim ◽

Donghyuk Kim ◽

Gunwoo Ha ◽

...

Keyword(s):

Real Time ◽

Rapid Test ◽

Epidemiological Surveillance ◽

Watery Diarrhoea ◽

Rt Pcr ◽

Immunochromatographic Strip ◽

Test Kit ◽

Porcine Epidemic Diarrhoea Virus ◽

Diarrhoea Virus ◽

Strip Test

Porcine epidemic diarrhoea virus (PEDV) causes acute and severe watery diarrhoea and dehydration, as well as 50–100 per cent mortality in piglets. For the PEDV diagnosis, a rapid test kit that is specific and sensitive to PEDV is critical to monitor this disease at pig farms. The present study aimed to develop an immunochromatographic assay (ICA) strip test for detecting PEDV in faecal swabs. The newly developed diagnostic test showed a detection limit of 104.0TCID50/ml of PEDV. Using faecal swab samples, the relative sensitivity and specificity of the ICA kit were 95.0 per cent and 98.6 per cent, respectively, compared with those of real-time RT-PCR. In samples from piglets experimentally infected with PEDV, the results showed 100 per cent agreement with those found by real-time RT-PCR. Our developed test strip will be useful for rapid diagnosis and can be used for epidemiological surveillance of PEDV infection.

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ANTI-HIV DAN SUBTIPE HIV PADA PASIEN HEMODIALISIS

INDONESIAN JOURNAL OF CLINICAL PATHOLOGY AND MEDICAL LABORATORY ◽

10.24293/ijcpml.v22i2.1124 ◽

2018 ◽

Vol 22 (2) ◽

pp. 182

Author(s):

Retno Handajani ◽

Mochammad Thaha ◽

Mochamad Amin ◽

Citrawati Dyah Kencono Wungu ◽

Edhi Rianto ◽

...

Keyword(s):

Rapid Test ◽

Rt Pcr ◽

Hiv Rna ◽

Hemodialysis Unit ◽

Test Kit ◽

Ckd Stage ◽

Immunodeficiency Virus ◽

Low Levels ◽

Anti Hiv ◽

Hiv 1

Anti-Human Immunodeficiency Virus (Anti-HIV) was performed from 100 plasma Chronic Kidney Disease (CKD) stage 5 patientswith continuous hemodialysis (HD) at the Hemodialysis Instalation Dr Soetomo hospital, Surabaya, Indonesia, using three (3) kind ofreagents: Tri-line HIV Rapid test Device from Acon for HIV 1/2/O as strips form, Foresight HIV 1/2/O Antibody EIA Test Kit from Aconand Anti-HIV 1+2/Subtype O ELISA from Axiom. HIV RNA and HIV subtype were detected by Reverse Transcription Polymerase ChainReaction (RT-PCR) based on HIV gag region and analysis of DNA result. Seventy three % patients were hemodialysed twice in a week andonly 14% with duration more than five (5) years. Most of the patients (43%) were hemodialysed between 100−300 times. From the 100plasma samples was obtained only one (1%) man patient plasma sample with positive anti-HIV. A weak positive of RT-PCR result wasnot succeed to be sequenced for determining the HIV subtype. This cause was suspected due to low levels of HIV RNA in blood. The resultsof this study was expected can be used as an additional management consideration of hemodialysis patients at the Hemodialysis Unit.

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

10.36106/ijsr/1335520 ◽

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.

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Socio-demographic characteristics and Iodine status of the school-going children of Suryodaya Municipality, Ilam

Journal of Food Science and Technology Nepal ◽

10.3126/jfstn.v12i12.23868 ◽

2020 ◽

Vol 12 (12) ◽

pp. 31-36

Author(s):

Babita Adhikari ◽

Praja Adhikari

Keyword(s):

School Children ◽

Urinary Iodine ◽

Rapid Test ◽

Iodine Content ◽

Primary School Children ◽

Test Kit ◽

Iodine Excretion ◽

Study Population ◽

Salt Iodine ◽

Urine Iodine

Iodine deficiency disorder (IDD) is a major micronutrient deficiency problem in Nepal. This study was conducted with objective to measure the Urinary iodine excretion (UIE) and attempts were made to relate urinary iodine with salt use and other sociodemographic variables of household of primary school children of Suryodaya municipality of Ilam district of Nepal. A community based cross section study was conducted in two schools of study area selected randomly (lottery method). A total of 202 school children of 6-12 years were recruited for the study to collect urine and salt samples for urine iodine content (UIC) and salt iodine content (SIC) measurement respectively and detail information of study population was achieved from their household. UIC was measured by ammonium persulphate digestion microplate (APDM) method and SIC was estimated by rapid test kit (RTK). Data were expressed in frequency, mean±SD and median (IQR) according to the nature of data. Chi-square test, Mann-Whitney U test and Kruskal-Wallis test were used to test the significance considering p≤0.05 at 95% confidence interval. It was found that Median UIC of the study population was 152.14 µg/L. Overall; it was found that 30.7% children had urine iodine level less than the normal WHO levels. The availability of adequately iodized salt was 93.1% as measured by RTK. There was statically significant association between consumed salt iodine content and urine iodine excretion level (P < 0.05).

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