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1.
Ann Clin Lab Sci ; 52(2): 332-335, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1787119

ABSTRACT

OBJECTIVE: Although real-time reverse transcription-PCR (RT-PCR) is the gold standard for diagnosing coronavirus disease 2019 (COVID-19), simpler and faster antibody detection tests can be complementary for diagnosis of COVID-19. To manage the COVID-19 pandemic, the need for serologic testing has increased. In this report, the newly developed antibody detection assays ACCEL ELISA COVID-19 (ACCEL) and Elecsys anti-SARS-CoV-2 (Elecsys) were evaluated. METHODS: Serum samples submitted for routine laboratory testing were analyzed (66 and 161 PCR-positive and PCR-negative samples). After the samples were aliquoted, antibody detection tests were performed using ACCEL and Elecsys assays. RESULTS: When detection of viral RNA using RT-PCR was set as the reference method for diagnosis of COVID-19, the sensitivity was 83.3% and 75.8, and the specificity was 96.9 and 99.4% in ACCEL and Elecsys, respectively. The true positivity rates of ACCEL and Elecsys assays were 57.1%/42.9%, 57.1%/28.6%, 77.8%/66.7%, and 97.1%/97.1% among the specimens collected ≤3, 4-7, 8-14, and >14 days after symptom onset, respectively. CONCLUSIONS: The ACCEL assay showed high sensitivity in samples collected within 7 days after symptom onset. Because many patients are asymptomatic in the early stage of SARS-CoV-2 infection, the ACCEL assay could be a good screening tool due to high sensitivity in the early stage of SARS-CoV-2 infection.


Subject(s)
COVID-19 , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Humans , Pandemics , SARS-CoV-2 , Sensitivity and Specificity
2.
PLoS One ; 16(10): e0258394, 2021.
Article in English | MEDLINE | ID: covidwho-1456095

ABSTRACT

Rapid antigen (Ag) tests for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) provide quick results, do not require specialized technical skills or infrastructure, and can be used as a point-of-care method to prevent the spread of coronavirus disease (COVID-19). The performance of a magnetic force-assisted electrochemical immunoassay-based test, namely the MARK-B COVID-19 Ag test (BBB, Sungnam, Republic of Korea), was evaluated using 170 nasopharyngeal swab specimens and compared to that of RT-PCR and commercial rapid Ag test (STANDARD Q COVID-19 Ag Test, SD Biosensor, Suwon-si, Republic of Korea). The overall sensitivity and specificity of the MARK-B test were 90.0% (95% CI 79.4%-96.2%) and 99.0% (95% CI 95.0%-99.9%), respectively, with a kappa coefficient of 0.908. The correlations between the electrical current values of MARK-B and the Ct values of RT-PCR were -0.898 (E gene, 95% CI -0.938 to -0.834) and -0.914 (RdRp gene, 95% CI -0.948 to -0.860), respectively. The limit of detection of the MARK-B was measured using the viral culture reference samples and found to be 1 x 102 pfu/mL. The magnetic force-assisted electrochemical immunoassay-based Ag test can be used to rapidly detect SARS-CoV-2 infections, and the corresponding fully automated portable device can provide easy readability and semi-quantitative results.


Subject(s)
Antigens, Viral/immunology , COVID-19 Serological Testing , COVID-19 , Electrochemical Techniques , Magnetic Fields , SARS-CoV-2/immunology , COVID-19/diagnosis , COVID-19/immunology , Humans , Immunoassay , Republic of Korea
3.
Ann Lab Med ; 41(6): 577-587, 2021 Nov 01.
Article in English | MEDLINE | ID: covidwho-1264321

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays have high clinical utility in managing the pandemic. We compared antibody responses and seroconversion of coronavirus disease 2019 (COVID-19) patients using different immunoassays. METHODS: We evaluated 12 commercial immunoassays, including three automated chemiluminescent immunoassays (Abbott, Roche, and Siemens), three enzyme immunoassays (Bio-Rad, Euroimmun, and Vircell), five lateral flow immunoassays (Boditech Med, SD biosensor, PCL, Sugentech, and Rapigen), and one surrogate neutralizing antibody assay (GenScript) in sequential samples from 49 COVID-19 patients and 10 seroconversion panels. RESULTS: The positive percent agreement (PPA) of assays for a COVID-19 diagnosis ranged from 84.0% to 98.5% for all samples (>14 days after symptom onset), with IgM or IgA assays showing higher PPAs. Seroconversion responses varied across the assay type and disease severity. Assays targeting the spike or receptor-binding domain protein showed a tendency for early seroconversion detection and higher index values in patients with severe disease. Index values from SARS-CoV-2 binding antibody assays (three automated assays, one LFIA, and three EIAs) showed moderate to strong correlations with the neutralizing antibody percentage (r=0.517-0.874), and stronger correlations in patients with severe disease and in assays targeting spike protein. Agreement among the 12 assays was good (74.3%-96.4%) for detecting IgG or total antibodies. CONCLUSIONS: Positivity rates and seroconversion of SARS-CoV-2 antibodies vary depending on the assay kits, disease severity, and antigen target. This study contributes to a better understanding of antibody response in symptomatic COVID-19 patients using currently available assays.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Testing/methods , COVID-19/diagnosis , SARS-CoV-2/immunology , COVID-19/pathology , COVID-19/virology , Humans , Immunoassay , Immunoglobulin A/analysis , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Reagent Kits, Diagnostic , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Severity of Illness Index
4.
PLoS One ; 15(8): e0237692, 2020.
Article in English | MEDLINE | ID: covidwho-717607

ABSTRACT

BACKGROUND: Our hospital experienced the first healthcare-associated COVID-19 outbreak in Seoul at the time the first COVID-19 cases were confirmed in Korea. The first confirmed COVID-19 patient was a hospital personnel who was in charge of transferring patients inside our hospital. To contain the virus spread, we shutdown our hospital, and tested all inpatients, medical staff members, and employees. METHODS: We retrospectively analyzed the results of SARS-CoV-2 RT-PCR testing according to the contact history, occupation, and presence of respiratory symptoms. Closed-circuit television (CCTV) was reviewed in the presence of an epidemiologist to identify individuals who came into contact with confirmed COVID-19 patients. RESULTS: A total of 3,091 respiratory samples from 2,924 individuals were obtained. Among 2,924 individuals, two inpatients, and one caregiver tested positive (positivity rate, 0.1%). Although all confirmed cases were linked to a general ward designated for pulmonology patients, no medical staff members, medical support personnel, or employees working at the same ward were infected. Contact with confirmed COVID-19 cases was frequent among inpatients and medical support personnel. The most common contact area was the general ward for pulmonology patients and medical support areas, including clinical and imaging examination rooms. Finally, the total number of hospital-associated infections was 14, consisting of four diagnosed at our hospital and ten diagnosed outside the hospital. CONCLUSIONS: The robust control of the COVID-19 outbreak further minimized the transmission of SARS-CoV-2 in the hospital and local communities. However, there was also a debate over the appropriate period of hospital shutdown and testing of all hospital staff and patients. Future studies are required to refine and establish the in-hospital quarantine and de-isolation guidelines based on the epidemiological and clinical settings.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Cross Infection/epidemiology , Cross Infection/prevention & control , Disease Transmission, Infectious/prevention & control , Hospitals, University , Pandemics/prevention & control , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Adult , Aged , Aged, 80 and over , COVID-19 , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Cross Infection/virology , Female , Health Personnel , Humans , Male , Middle Aged , Patients' Rooms , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Quarantine/methods , Retrospective Studies , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Seoul/epidemiology , Young Adult
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