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1.
Iran J Immunol ; 18(1): 82-92, 2021 03.
Article in English | MEDLINE | ID: covidwho-2067500

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly transmits in general population, mainly between health-care workers (HCWs) who are in close contact with patients. OBJECTIVE: To study the seropositivity of HCWs as a high-risk group compared to general population. METHODS: 72 samples were obtained from HCWs working in Masih Daneshvari hospital as one of the main COVID-19 admission centers in Tehran, during April 4 to 6, 2020. Also we collected 2021 blood samples from general population. The SARS-CoV-2 specific IgM, and IgG antibodies in the collected serum specimens were measured by commercial ELISA kits. RESULTS: Based on the clinical manifestations, 25.0%, 47.2%, and 27.8% of HCWs were categorized as symptomatic with typical symptoms, symptomatic with atypical symptoms, and asymptomatic, respectively. Symptomatic individuals with typical and atypical symptoms were 63.2% and 36.8% positive in RT-PCR test, respectively. Anti-SARS-CoV-2 IgM and IgG antibodies were detected in 15.3% and 27.8% of HCWs samples, respectively. Antibody testing in the general population indicated that SARS-CoV-2 specific IgM and IgG were found in (162/2021) 8%, and (290/2021) 14.4%, respectively. The frequency of positive cases of IgM and IgG were significantly increased in HCWs compared to general population (p= 0.028 for IgM and p= 0.002 for IgG). CONCLUSION: The frequency of SARS-CoV-2 specific antibodies in HCWs was higher than general population indicating a higher viral transmission via close exposure with COVID-19 patients.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19/diagnosis , Health Personnel , Occupational Health , SARS-CoV-2/immunology , Adult , Aged , Biomarkers/blood , COVID-19/epidemiology , COVID-19/immunology , COVID-19/virology , Cross-Sectional Studies , Female , Host-Pathogen Interactions , Humans , Infectious Disease Transmission, Patient-to-Professional , Iran/epidemiology , Male , Middle Aged , Occupational Exposure , Predictive Value of Tests , Risk Factors , Seroepidemiologic Studies , Time Factors , Young Adult
2.
PLoS One ; 17(3): e0264929, 2022.
Article in English | MEDLINE | ID: covidwho-1938420

ABSTRACT

BACKGROUND: People experiencing homelessness who live in congregate shelters are at high risk of SARS-CoV2 transmission and severe COVID-19. Current screening and response protocols using rRT-PCR in homeless shelters are expensive, require specialized staff and have delays in returning results and implementing responses. METHODS: We piloted a program to offer frequent, rapid antigen-based tests (BinaxNOW) to residents and staff of congregate-living shelters in San Francisco, California, from January 15th to February 19th, 2021. We used the Reach-Effectiveness-Adoption-Implementation-Maintenance (RE-AIM) framework to evaluate the implementation. RESULTS: Reach: We offered testing at ten of twelve eligible shelters. Shelter residents and staff had variable participation across shelters; approximately half of eligible individuals tested at least once; few tested consistently during the study. Effectiveness: 2.2% of participants tested positive. We identified three outbreaks, but none exceeded 5 cases. All BinaxNOW-positive participants were isolated or left the shelters. Adoption: We offered testing to all eligible participants within weeks of the project's initiation. Implementation: Adaptations made to increase reach and improve consistency were promptly implemented. Maintenance: San Francisco Department of Public Health expanded and maintained testing with minimal support after the end of the pilot. CONCLUSION: Rapid and frequent antigen testing for SARS-CoV2 in homeless shelters is a viable alternative to rRT-PCR testing that can lead to immediate isolation of infectious individuals. Using the RE-AIM framework, we evaluated and adapted interventions to enable the expansion and maintenance of protocols.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , Homeless Persons/statistics & numerical data , COVID-19/immunology , COVID-19 Testing/methods , California , Disease Outbreaks/prevention & control , Housing , Humans , Immunologic Tests/methods , Mass Screening/methods , Pilot Projects , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , San Francisco
3.
Diagn Microbiol Infect Dis ; 104(3): 115763, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-1914300

ABSTRACT

BACKGROUND: The gold standard for COVID-19 diagnosis-reverse-transcriptase polymerase chain reaction (RT-PCR)- is expensive and often slow to yield results whereas lateral flow tests can lack sensitivity. METHODS: We tested a rapid, lateral flow antigen (LFA) assay with artificial intelligence read (LFAIR) in subjects from COVID-19 treatment trials (N = 37; daily tests for 5 days) and from a population-based study (N = 88; single test). LFAIR was compared to RT-PCR from same-day samples. RESULTS: Using each participant's first sample, LFAIR showed 86.2% sensitivity (95% CI 73.6%-98.8) and 94.3% specificity (88.8%-99.7%) compared to RT-PCR. Adjusting for days since symptom onset and repeat testing, sensitivity was 97.8% (89.9%-99.5%) on the first symptomatic day and decreased with each additional day. Sensitivity improved with artificial intelligence (AI) read (86.2%) compared to the human eye (71.4%). CONCLUSION: LFAIR showed improved accuracy compared to LFA alone. particularly early in infection.


Subject(s)
Antigens, Viral , Artificial Intelligence , COVID-19 Serological Testing , COVID-19 , SARS-CoV-2 , Antigens, Viral/analysis , Antigens, Viral/immunology , COVID-19/diagnosis , COVID-19/immunology , COVID-19/virology , COVID-19 Nucleic Acid Testing , COVID-19 Serological Testing/methods , COVID-19 Serological Testing/standards , Clinical Trials as Topic , Humans , Reproducibility of Results , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Time Factors
4.
PLoS One ; 17(5): e0267566, 2022.
Article in English | MEDLINE | ID: covidwho-1910605

ABSTRACT

BACKGROUND: To control COVID-19 pandemic is of critical importance to the global public health. To capture the prevalence in an accurate and timely manner and to understand the mode of nosocomial infection are essential for its preventive measure. METHODS: We recruited 685 healthcare workers (HCW's) at Tokyo Shinagawa Hospital prior to the vaccination with COVID-19 vaccine. Sera of the subjects were tested by assays for the titer of IgG against S protein's receptor binding domain (IgG (RBD)) or IgG against nucleocapsid protein (IgG (N)) of SARS-CoV-2. Together with PCR data, the positive rates by these methods were evaluated. RESULTS: Overall positive rates among HCW's by PCR, IgG (RBD), IgG (N) with a cut-off of 1.4 S/C (IgG (N)1.4), and IgG (N) with a cut-off of 0.2 S/C (IgG (N)0.2) were 3.5%, 9.5%, 6.1%, and 27.7%, respectively. Positive rates of HCW's working in COVID-19 ward were significantly higher than those of HCW's working in non-COVID-19 ward by all the four methods. Concordances of IgG (RBD), IgG (N)1.4, and IgG (N)0.2 against PCR were 97.1%, 71.4%, and 88.6%, respectively. By subtracting the positive rates of PCR from that of IgG (RBD), the rate of overall silent infection and that of HCW's in COVID-19 ward were estimated to be 6.0% and 21.1%, respectively. CONCLUSIONS: For the prevention of nosocomial infection of SARS-CoV-2, identification of silent infection is essential. For the detection of ongoing infection, periodical screening with IgG (RBD) in addition to PCR would be an effective measure. For the surveillance of morbidity in the population, on the other hand, IgG (N)0.2 could be the most reliable indicator among the three serological tests.


Subject(s)
COVID-19 Serological Testing , COVID-19 , Cross Infection , Antibodies, Viral , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19 Serological Testing/methods , Cross Infection/diagnosis , Cross Infection/epidemiology , Cross Infection/prevention & control , Humans , Immunoglobulin G , Japan , Pandemics , SARS-CoV-2 , Serologic Tests/methods , Spike Glycoprotein, Coronavirus
5.
Sci Rep ; 12(1): 586, 2022 01 12.
Article in English | MEDLINE | ID: covidwho-1900539

ABSTRACT

The performance of a laboratory-developed IgG/IgA flow cytometry-based immunoassay (FCI) using Jurkat T cells stably expressing full-length native S protein was compared against Elecsys electrochemiluminiscent (ECLIA) Anti-SARS-CoV-2 S (Roche Diagnostics, Pleasanton, CA, USA), and Liaison SARS-CoV-2 TrimericS IgG chemiluminiscent assay (CLIA) (Diasorin S.p.a, Saluggia, IT) for detection of SARS-CoV-2-specific antibodies. A total of 225 serum/plasma specimens from 120 acute or convalescent COVID-19 individuals were included. Overall, IgG/IgA-FCI yielded the highest number of positives (n = 179), followed by IgA-FCI (n = 177), Roche ECLIA (n = 175), IgG-FCI (n = 172) and Diasorin CLIA (n = 154). For sera collected early after the onset of symptoms (within 15 days) IgG/IgA-FCI also returned the highest number of positive results (52/72; 72.2%). Positive percent agreement between FCI and compared immunoassays was highest for Roche ECLIA, ranging from 96.1 (IgG/IgA-FCI) to 97.7% (IgG-FCI), whereas negative percent agreement was higher between FCI and Diasosin CLIA, regardless of antibody isotype. The data suggest that FCI may outperform Roche ECLIA and Diasorin CLIA in terms of clinical sensitivity for serological diagnosis of SARS-CoV-2 infection.


Subject(s)
Antibodies, Viral/blood , Flow Cytometry/methods , Immunoassay/methods , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Viral/immunology , COVID-19 Serological Testing , Humans , Jurkat Cells , Retrospective Studies , Sensitivity and Specificity
6.
Viruses ; 14(6)2022 06 02.
Article in English | MEDLINE | ID: covidwho-1896924

ABSTRACT

A robust serological test to measure neutralizing antibodies against SARS-CoV-2 in biosafety level-2 (BSL-2) laboratories is useful for monitoring antibody response after vaccination or natural infection. The gold standard assay is the conventional plaque reduction neutralization test (PRNT) which requires extensive labor, live viruses, and BSL-3 facilities. Recently, we developed a novel single-round infection fluorescent SARS-CoV-2 virus (SFV) that can be safely used at BSL-2 laboratories for high-throughput neutralization and antiviral testing. In this study, we evaluated the performance of the neutralization test using this SFV with 80 PRNT-positive and 92 PRNT-negative clinical serum or plasma specimens. The SFV neutralization test (SFVNT) has 100% sensitivity and specificity compared to the PRNT. Furthermore, the neutralizing titers generated by the SFVNT and PRNT are highly correlated, with R2 = 0.903 (p < 0.0001). Due to high sensitivity, specificity, accuracy, and reproducibility, the SFVNT can be deployed for the large-scale testing of COVID-19 patients or vaccinated people in general lab settings.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/diagnosis , COVID-19 Serological Testing , Containment of Biohazards , Humans , Laboratories , Neutralization Tests , Reproducibility of Results
7.
Infect Dis (Lond) ; 54(10): 731-737, 2022 10.
Article in English | MEDLINE | ID: covidwho-1868224

ABSTRACT

BACKGROUND: Current method for diagnosis of SARS-CoV-2 infection is an RT-PCR test on the nasopharyngeal or oropharyngeal swab. Rapid diagnosis is essential for containing viral spread and triage of symptomatic patients presenting to hospital ER departments. As a faster alternative to RT-PCR, we evaluated a SARS-Cov-2 Rapid Antigen test in symptomatic patients presenting to hospital ER departments. METHODS: We evaluated the diagnostic performance of the Roche SARS-CoV-2 Rapid Antigen test (SD Biosensor) for detection of SARS-CoV-2 compared to RT-PCR. RESULTS: Our study showed inferior performance of the SARS-CoV-2 Rapid Antigen test for detection of SARS-CoV-2. Firstly, because of the lack of specificity, which is potentially life-threatening due to the association of nosocomial-acquired SARS-CoV-2 infection. Secondly, with a sensitivity of 45.5%, it is impossible to rule out SARS-CoV-2 infection, resulting in reflex PCR-testing. Comparison of viral load in RT-PCR positive samples with corresponding antigen results showed a significant difference between antigen positive and negative samples. COVID-19 infection will not be detected in patients admitted to the hospital in an early or late phase, typically associated with low viral loads. Sensitivity increases when testing within 5-7 symptomatic days, but the implementation of this cut-off is impractical in ER settings. However, diagnostic performance is better to detect high viral load (> = 5 log10 copies/mL) linked with contagiousness. CONCLUSION: Our study showed inferior performance of the Roche SARS-CoV-2 Rapid Antigen test (SD Biosensor) for detection of SARS-CoV-2 which limits its use as a diagnostic gatekeeper in ER departments, but is able to differentiate contagious individuals.


Subject(s)
COVID-19 Serological Testing , COVID-19 , Antigens, Viral , COVID-19/diagnosis , Emergency Service, Hospital , Humans , SARS-CoV-2 , Sensitivity and Specificity
10.
PLoS One ; 17(2): e0262442, 2022.
Article in English | MEDLINE | ID: covidwho-1854992

ABSTRACT

In late December 2019, pneumonia cases of unknown origin were reported in Wuhan, China. This virus was named SARS-CoV2 and the clinical syndrome was named coronavirus disease 19 (COVID-19). South Africa, despite strict and early lockdown has the highest infection rate in Africa. A key component of South Africa's response to SARSCoV2 was the rapid scale-up of diagnostic testing. The Abbott SARS-CoV2 assay detects IgG antibodies against the Nucleocapsid (N) protein of the SARS-CoV2 virus. This study undertook to validate and evaluate performance criteria of the Abbott assay and to establish whether this assay would show clinical utility in our population. Positive patients (n = 391) and negative controls (n = 139) were included. The Architect-i and Alinity-i systems were analyzers that were used to perform the SARS-CoV-2 IgG assay. In-house ELISA was incorporated into the study as a confirmatory serology test. A total of number of 530 participants was tested, 87% were symptomatic with infection and 13% were asymptomatic. When compared to RT-qPCR, the sensitivity of Architect and Alinity SARS-CoV2 assays was 69.5% and 64.8%, respectively. Specificity for Architect and Alinity assays was 95% and 90.3%, respectively. The Abbott assay was also compared to in house ELISA assay, with sensitivity for the Architect and Alinity assays of 94.7% and 92.5%, respectively. Specificity for Abbott Alinity assays was 91.7% higher than Abbott Architect 88.1%. Based on the current findings testing of IgG after 14 days is recommended in South Africa and supports other studies performed around the world.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoglobulin G/blood , SARS-CoV-2/isolation & purification , Adult , Aged , Aged, 80 and over , Antibodies, Viral/immunology , COVID-19/blood , COVID-19/epidemiology , COVID-19/virology , Enzyme-Linked Immunosorbent Assay , Female , Follow-Up Studies , Humans , Immunoglobulin G/immunology , Male , Middle Aged , Prognosis , Retrospective Studies , South Africa/epidemiology , Young Adult
12.
J Appl Lab Med ; 7(3): 698-710, 2022 05 04.
Article in English | MEDLINE | ID: covidwho-1831206

ABSTRACT

BACKGROUND: Numerous serology assays are available for detection of SARS-CoV-2 antibodies but are limited in that only 1 or 2 target antigen(s) can be tested at a time. Here, we describe a novel multiplex assay that simultaneously detects and quantifies IgG antibodies to SARS-CoV-2 antigens, spike (S), nucleocapsid (N), receptor-binding domain (RBD), and N-terminal domain (NTD) in a single well. METHODS: Sensitivity was determined using samples (n = 124) from confirmed SARS-CoV-2 RT-PCR positive individuals. Prepandemic (n = 100) and non-COVID respiratory infection positive samples (n = 100) were used to evaluate specificity. Samples were analyzed using COVID-19 IgG multiplex serology assay from Meso Scale Discovery (MSD) and using commercial platforms from Abbott, EUROIMMUN, and Siemens. RESULTS: At >14 days post-PCR, MSD assay displayed >98.0% sensitivity [S 100% (95% CI 98.0%-100.0%); N 98.0% (95% CI 97.2%-98.9%); RBD 94.1% (95% CI 92.6%-95.6%); NTD 98.0% (95% CI, 97.2%-98.9%)] and 99% specificity (95% CI 99.3%-99.7%) for antibodies to all 4 antigens. Parallel assessment of antibodies to more than 1 antigen improved the sensitivity to 100% (95% CI 98.0%-100.0%) while maintaining 98% (95% CI 97.6%-98.4%) specificity regardless of the combinations used. When AU/mL concentrations of IgG antibodies from the MSD assay were compared against the corresponding IgG signals acquired from the single target commercial assays, the following correlations were observed: Abbott (vs MSD N, R2 = 0.73), Siemens (vs MSD RBD, R2 = 0.92), and EUROIMMUN (vs MSD S, R2 = 0.82). CONCLUSION: MSD assay offers an accurate and a comprehensive assessment of SARS-CoV-2 antibodies with higher sensitivity and equivalent specificity compared to the commercial IgG serology assays.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/diagnosis , COVID-19 Serological Testing , Humans , Immunoglobulin G , Sensitivity and Specificity
13.
J Infect Chemother ; 28(6): 840-843, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-1828872

ABSTRACT

INTRODUCTION: Since respiratory sample collection is an uncomfortable experience, simultaneous detection of pathogens with a single swab is preferable. We prospectively evaluated the clinical performance of a newly developed antigen test QuickNavi-Flu+COVID19 Ag (Denka Co., Ltd., Tokyo, Japan) which can detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses at the same time with a single testing device. METHODS: We included those who were suspected of contracting coronavirus disease 2019 (COVID-19) and were referred to a PCR center at Ibaraki prefecture in Japan, between August 2, 2021 to September 13, 2021, when the variant carrying L452R spike mutation of SARS-CoV-2 were prevalent. Additional nasopharyngeal samples and anterior nasal samples were obtained for the antigen test and were compared with a reference real-time reverse transcription PCR (RT-PCR) using nasopharyngeal samples. RESULTS: In total, 1510 nasopharyngeal samples and 862 anterior nasal samples were evaluated. During the study period, influenza viruses were not detected by QuickNavi-Flu+COVID19 Ag and reference real-time RT-PCR. For SARS-CoV-2 detection in nasopharyngeal samples, the sensitivity and specificity of the antigen test were 80.9% and 99.8%, respectively. The sensitivity and specificity using anterior nasal samples were 67.8% and 100%, respectively. In symptomatic cases, the sensitivities increased to 88.3% with nasopharyngeal samples and 73.7% with anterior nasal samples. There were three cases of discrepant results between the antigen test and the real-time RT-PCR. All of them were positive with the antigen test but negative with the real-time RT-PCR in SARS-CoV-2 detection. CONCLUSION: A combo kit, QuickNavi-Flu+COVID19 Ag, showed an acceptable sensitivity and sufficient specificity for SARS-CoV-2 detection, especially using nasopharyngeal sample collected from symptomatic patients.


Subject(s)
COVID-19 , Antigens, Viral/analysis , COVID-19/diagnosis , COVID-19 Serological Testing , Humans , Nasopharynx , SARS-CoV-2/genetics , Sensitivity and Specificity
14.
J Infect Chemother ; 28(6): 780-785, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-1828867

ABSTRACT

INTRODUCTION: The diagnostic accuracy of antigen testing of anterior nasal (AN) samples for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has not been evaluated in the Japanese population. This study assessed the diagnostic accuracy of the Roche SARS-CoV-2 rapid antigen test (rapid antigen test) using AN samples. METHODS: Two AN samples and one nasopharyngeal (NP) sample were collected from individuals undergoing screening for SARS-CoV-2 infection. The results of the rapid antigen test and the reverse-transcription polymerase chain reaction (RT-PCR) test using AN samples were compared to those of RT-PCR tests using NP samples. RESULTS: Samples were collected from 800 participants, 95 and 110 of whom tested positive for SARS-CoV-2 on RT-PCR tests of AN and NP samples, respectively. The overall sensitivity/specificity of the AN rapid antigen test and AN RT-PCR were 72.7%/100% and 86.4%/100%, respectively. In symptomatic cases, the sensitivities of the AN rapid antigen test and AN RT-PCR were 84.7% and 94.9%, respectively. In asymptomatic cases, the sensitivities of the AN rapid antigen test and AN RT-PCR were 58.8% and 76.5%, respectively. The sensitivity of the AN rapid antigen test was over 80% in cases with cycle threshold (Ct) values < 25; it significantly decreased with an increase in the Ct values (p < 0.001). CONCLUSION: The rapid antigen test with AN samples had a favorable sensitivity, especially in symptomatic cases or in cases with Ct values < 25. It gave no false-positive results. Compared with AN-RT PCR, the AN rapid antigen test had a modestly lower sensitivity in asymptomatic cases.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19 Serological Testing , Humans , Nasopharynx , Prospective Studies , SARS-CoV-2/genetics , Sensitivity and Specificity
15.
Front Public Health ; 10: 836328, 2022.
Article in English | MEDLINE | ID: covidwho-1809615

ABSTRACT

Real-world data are needed to establish SARS-CoV-2 rapid antigen testing (RAT) as an effective and reliable approach for SARS-CoV-2 screening. This study included 1,952,931 individuals who provided upper respiratory specimens during SARS-CoV-2 screening at CityMD urgent care locations in the New York metropolitan area from October 2020 to March 2021. Positive and negative results, as determined by the BD Veritor™ System for Rapid Detection of SARS-CoV-2 antigen (Veritor), were obtained for all individuals, with reflex reverse transcriptase-polymerase chain reaction (RT-PCR) testing performed on a case-by-case basis, per standard of care. Using verification bias adjustment, two alternative model assumptions were utilized for RAT results with missing reflex RT-PCR results. The worst antigen diagnostic performance estimates asserted that missing RT-PCR results would show a distribution similar to those RT-PCR results actually obtained, based on symptom category. The best antigen diagnostic performance estimates asserted that individuals without RT-PCR results had a clinical presentation consistent with RAT results, and, therefore, missing RT-PCR results would agree with RAT results. For patients with symptoms or high-risk exposure, 25.3% (n = 86,811/343,253) of RAT results were positive; vs. 3.4% (n = 53,046/1,559,733) positive for asymptomatic individuals without high-risk exposure. Reflex RT-PCR results were obtained from 46.3% (n = 158,836/343,253) and 13.8% (n = 215,708/1,559,733) of symptomatic and asymptomatic individuals, respectively. RT-PCR confirmed 94.4% (4,265/4,518) of positive and 90.6% (139,759/154,318) of negative RAT results in symptomatic individuals; and confirmed 83.4% (6,693/8,024) of positive and 95.3% (197,955/207,684) of negative RAT results in asymptomatic individuals. Applied assumptions for missing reflex RT-PCR results led to worst performance sensitivity estimates of 77.2 and 38.5% in the symptomatic and asymptomatic populations, respectively; assumptions for best performance estimates led to sensitivity values of 85.6 and 84.2%, respectively. Specificity values, regardless of assumptions or symptom category, ranged from 97.9-99.9%. At 10% SARS-CoV-2 prevalence, RAT positive predictive value was 86.9 and 99.0% for worst and best performance estimates across the total population, respectively; negative predictive values were >95% regardless of the applied assumption. Veritor test performance was consistent with that listed in the manufacturer instructions for use for symptomatic individuals. Real-world evidence should be gathered on RATs to support their efficacy as SARS-CoV-2 persists.


Subject(s)
COVID-19 Serological Testing , COVID-19 , COVID-19/diagnosis , COVID-19 Nucleic Acid Testing , Humans , SARS-CoV-2 , Sensitivity and Specificity
16.
J Clin Lab Anal ; 36(6): e24410, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-1797873

ABSTRACT

BACKGROUND: Surveillance and control of SARS-CoV-2 outbreak through gold standard detection, that is, real-time polymerase chain reaction (RT-PCR), become a great obstacle, especially in overwhelming outbreaks. In this study, we aimed to analyze the performance of rapid antigen home test (RAHT) as an alternative detection method compared with RT-PCR. METHODS: In total, 79 COVID-19-positive and 217 COVID-19-negative patients confirmed by RT-PCR were enrolled in this study. A duration from symptom onset to COVID-19 confirmation of <5 days was considered a recruiting criterion for COVID-19-positive cases. A nasal cavity specimen was collected for the RAHT, and a nasopharyngeal swab specimen was collected for RT-PCR. RESULTS: Sensitivity of the STANDARD Q COVID-19 Ag Home Test (SD Biosensor, Korea), compared with RT-PCR, was 94.94% (75/79) (95% [confidence interval] CI, 87.54%-98.60%), and specificity was 100%. Sensitivity was significantly higher in symptomatic patients (98.00%) than in asymptomatic (89.66%) patients (p-value = 0.03). There was no difference in sensitivity according to the duration of symptom onset to confirmation (100% for 0-2 days and 96.97% for 3-5 days, respectively) (p-value = 1.00). The RAHT detected all 51 COVID-19 patients whose Ct values were ≤25 (100%), whereas sensitivity was 73.33% (11/15) among patients with Ct values >25 (p-value = 0.01). CONCLUSION: The RAHT showed an excellent sensitivity for COVID-19-confirmed cases, especially for those with symptoms. There was a decrease in sensitivity when the Ct value is over 25, indicating that RAHT screening may be useful during the early phase of symptom onset, when the viral numbers are higher and it is more transmissible.


Subject(s)
COVID-19 , Antigens, Viral/analysis , COVID-19/diagnosis , COVID-19 Serological Testing , Humans , Mass Screening/methods , SARS-CoV-2 , Sensitivity and Specificity
17.
J Infect Dev Ctries ; 16(3): 418-421, 2022 03 31.
Article in English | MEDLINE | ID: covidwho-1786131

ABSTRACT

INTRODUCTION: Rapid antigen tests to detect SARS-CoV-2 virus need to be validated. The purpose of clinical validation is to place the test into the everyday working process in health care institutions. METHODOLOGY: The clinical validation of Alltest Covid19 antigen test (Alltest, China) and Vivadiag Pro SARS- CoV-2 antigen tests (Vivacheck, China) started in four Slovenian health care institutions in December as a point-of-care test. Institutions compared the results of antigen tests to Seegene Allplex™ 2019-nCoV rt-PCR assay (SeeGene, South Korea) and Cobas 6800 SARS CoV-2 rt-PCR (Roche, USA). RESULTS: Sensitivity (90.6%, 95% CI = 84.94%-94.36%) and specificity (100%, 95% CI = 99.41%-100%) of Vivadiag Pro SARS CoV-2 Ag test were observed. While validating Alltest Covid19 Ag assay we got similar results (sensitivity 94.37%, 95% CI = 89.20% - 97.54%), specificity 100% (95% CI = 98.83% - 100%). CONCLUSIONS: Vivadiag Pro SARS CoV-2 Ag test and Alltest Covid19 test proved to be a good screening tool to detect SARS-CoV-2. The accurate information about the patient's status was available almost immediately and there was no need to wait for rt-PCR results. We could prevent further spread of the SARS-CoV-2 in primary care and hospital settings.


Subject(s)
COVID-19 , SARS-CoV-2 , Antigens, Viral/analysis , COVID-19/diagnosis , COVID-19 Serological Testing , Hospitals , Humans , SARS-CoV-2/genetics , Sensitivity and Specificity
18.
Klin Lab Diagn ; 65(11): 688-692, 2020 Dec 04.
Article in English | MEDLINE | ID: covidwho-1780383

ABSTRACT

The study presents the results of the creation and evaluation of the diagnostic characteristics of the rapid immunochromatographic test for the qualitative detection and differentiation of IgM/IgG antibodies to SARS-CoV-2 in human serum, plasma, and whole blood "ИХА-COVID-19-IgM / IgG". Have been tested some samples without antibodies to SARS-CoV-2 and a samples with two and one type of specific antibodies. The coincidence of the results of immunochromatographic analysis with the results of the immunochemiluminescent method was 87.2%. Test kit can be use as the rapid diagnostic test in the context of the COVID-19 pandemic and to assess the immune status of convalescents.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing , COVID-19/diagnosis , Immunoassay , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Humans
19.
Klin Lab Diagn ; 65(11): 683-687, 2020 Dec 04.
Article in English | MEDLINE | ID: covidwho-1780382

ABSTRACT

A new original Russian test kit for the detection of IgG-antibodies to the causative agent of COVID-19 - coronavirus SARS-CoV-2 by the method of enzyme-linked immunosorbent assay (ELISA) on a solid-phase «ELISA-SARS-CoV-2-AT-G¼ has been developed. In comparative tests with similar test systems «Vitrotest® SARS-CoV-2 IgG¼ (Vitrotest, Ukraine) and «Anti-SARS-Cov-2 ELISA (IgG)¼ (EUROIMMUN AG, Germany) high diagnostic efficiency of the new test system was shown.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Immunoglobulin G/analysis , Clinical Laboratory Techniques , Humans , Plasma , Reagent Kits, Diagnostic
20.
Sci Rep ; 12(1): 5812, 2022 04 06.
Article in English | MEDLINE | ID: covidwho-1778631

ABSTRACT

The utilization of vaccines to fight the spread of SARS-CoV-2 has led to a growing need for expansive serological testing. To address this, an EUA approved immunoassay for detection of antibodies to SARS-CoV-2 in venous serum samples was investigated for use with dried blood spot (DBS) samples. Results from self-collected DBS samples demonstrated a 98.1% categorical agreement to venous serum with a correlation (R) of 0.9600 while professionally collected DBS samples demonstrated a categorical agreement of 100.0% with a correlation of 0.9888 to venous serum. Additional studies were performed to stress different aspects of at-home DBS collection, including shipping stability, effects of interferences, and other sample-specific robustness studies. These studies demonstrated a categorical agreement of at least 95.0% and a mean bias less than ± 20.0%. Furthermore, the ability to track antibody levels following vaccination with the BioNTech/Pfizer vaccine was demonstrated with serial self-collected DBS samples from pre-dose (Day 0) out to 19 weeks.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19 Serological Testing , Dried Blood Spot Testing/methods , Humans
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