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Background: The coronavirus disease 2019 (COVID-19) pandemic has had a devastating impact worldwide, and timely detection and quarantine of infected patients are critical to prevent spread of disease. Serological antibody testing is an important diagnostic method used increasingly in clinics, although its clinical application is still under investigation. Methods: A meta-analysis was conducted to compare the diagnostic performance of severe acute respiratory syndrome coronavirus-2 antibody tests in patients with COVID-19. The test results analysed included: (1) IgM-positive but IgG-negative (IgM+IgG−); (2) IgG-positive but IgM-negative (IgG+IgM−); (3) both IgM-positive and IgG-positive (IgM+IgG+); (4) IgM-positive without IgG information (IgM+IgG+/−); (5) IgG-positive without IgM information (IgG+IgM+/−); (6) either IgM-positive or IgG-positive (IgM+ or IgG+); and (7) IgA-positive (IgA+). Results: Sixty-eight studies were included. Pooled sensitivities for IgM+IgG−, IgG+IgM−, IgM+IgG+, IgM+IgG+/−, IgG+IgM+/−, and IgM+ or IgG+ were 6%, 7%, 53%, 68%, 73% and 79% respectively. Pooled specificities ranged from 98% to 100%. IgA+ had a pooled sensitivity of 78% but a relatively low specificity of 88%. Tests conducted 2 weeks after symptom onset showed better diagnostic accuracy than tests conducted earlier. Chemiluminescence immunoassay and detection of S protein as the antigen could offer more accurate diagnostic results. Discussion: These findings support the supplemental role of serological antibody tests in the diagnosis of COVID-19. However, their capacity to diagnose COVID-19 early in the disease course could be limited.

A novel clinical assay for the detection and quantitation of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was adapted from an in-house, research-based enzyme-linked immunosorbent assay (ELISA). Development and validation were performed under regulatory guidelines, and the test obtained emergency use authorization (EUA) from the New York State Department of Health (NYSDOH) and the Food and Drug Administration (FDA). The Mount Sinai coronavirus disease 2019 (COVID-19) antibody assay is an orthogonal, quantitative direct ELISA test which detects antibodies reactive to the receptor binding domain (RBD) and the spike protein of the novel SARS-CoV-2. The assay is performed on 96-well plates coated with either SARS-CoV-2 recombinant RBD or spike proteins. The test is divided into two stages, a qualitative screening assay against RBD and a quantitative assay against the full-length spike protein. The test uses pooled high titer serum as a reference standard. Negative pre-COVID-19 and positive post-COVID-19, PCR-confirmed specimens were incorporated in each ELISA test run, and the assays were performed independently at two different locations.The Mount Sinai COVID-19 serology performed with high sensitivity and specificity, 92.5% (95% CI: 0.785–0.980) and 100% (CI: 0.939–1.000) respectively. Between-run precision was assessed with a single run repeated over 22 days; and within-run precision was assessed with 10 replicates per day over 22 days. Both were within reported acceptance criteria (CV ≤ 20%).This population-based study reveals the applicability and reliability of this novel orthogonal COVID-19 serology test for the detection and quantitation of antibodies against SARS-CoV-2, allowing a broad set of clinical applications, including the broad evaluation of SARS-CoV-2 seroprevalence and antibody profiling in different population subsets.

A new pandemic is ongoing in several parts of the world. The agent responsible is the newly emerged severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The symptoms associated with this virus are known as the coronavirus disease-2019 (COVID-19). In this review, we summarize the published data on virus specific antibodies in hospitalized patients with COVID-19 disease, patients recovered from the disease and the individuals who are asymptomatic with SARS-CoV-2 infections. The review highlights the following: i) an adjunct role of antibody tests in the diagnosis of COVID-19 in combination with RT-PCR; ii) status of antibodies from COVID-19 convalescent patients to select donors for plasma therapy; iii) the potential confounding effects of other coronaviruses, measles, mumps and rubella in antibody testing due to homology of certain viral genes; and iv) the role of antibody testing for conducting surveillance in populations, incidence estimation, contact tracing and epidemiologic studies.

Introduction: Numerous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests exists commercially; however, their performance using clinical samples is limited. Although insufficient to detect SARS-CoV-2 in the early phase of infection, antibody assays can be of great use for surveillance studies or for some coronavirus disease 2019 (COVID-19) patients presenting late to the hospital., Methods: This study evaluated the sensitivity and specificity of four commercial SARS-CoV-2 lateral flow antibody tests using 213 serum specimens from 90 PCR-positive confirmed COVID-19 patients. Of 59 negative control sera, 50 were obtained from patients with other respiratory infectious diseases before COVID-19 pandemic began while nine were from patients infected with other respiratory viruses, including two seasonal coronaviruses., Results: The varied sensitivities for the four commercial kits were 70.9%, 65.3%, 45.1%, and 65.7% for BioMedomics, Autobio Diagnostics, Genbody, and KURABO, respectively, between sick days 1 and 155 in COVID-19 patients. The sensitivities of the four tests gradually increased over time after infection before sick day 5 (15.0%, 12.5%, 15.0%, and 20.0%); from sick day 11-15 (95.7%, 87.2%, 53.2%, and 89.4%); and after sick day 20 (100%, 100%, 68.6%, and 96.1%), respectively. For severe illness, the sensitivities were quite high in the late phase after sick day 15. The specificities were over 96% for all four tests. No cross-reaction due to other pathogens, including seasonal coronaviruses, was observed., Conclusions: Our results demonstrated the large differences in the antibody test performances. This ought to be considered when performing surveillance analysis., (Copyright © 2021 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody tests of varying specificity and sensitivity are now available. For informing individuals whether they have had coronavirus disease 2019 (COVID-19), they need to be very accurate. For measuring population prevalence of past infection, the numbers of false positives and negatives need to be roughly equal. With a series of worked examples for a notional population of 100,000 people, we show that even test systems with a high specificity can yield a large number of false positive results, especially where the population prevalence is low. For example, at a true population prevalence of 5%, using a test with 99% sensitivity and specificity, 16% of positive results will be false and thus 950 people will be incorrectly informed they have had the infection. Further confirmatory testing may be needed. Giving false reassurance on which personal or societal decisions might be based could be harmful for individuals, undermine public confidence and foster further outbreaks., (Copyright © 2020 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.)