scholarly journals Accurate point-of-care serology tests for COVID-19

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248729
Author(s):  
Charles F. Schuler ◽  
Carmen Gherasim ◽  
Kelly O’Shea ◽  
David M. Manthei ◽  
Jesse Chen ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Point Of Care ◽  
Vaccine Response ◽  
Antibody Testing ◽  
Class Time ◽  
Antibody Assays ◽  
Antibody Class ◽  
Finger Stick ◽  
Almost All ◽  
Prior Infection

Background As COVID-19 vaccines become available, screening individuals for prior COVID-19 infection and vaccine response in point-of-care (POC) settings has renewed interest. We prospectively screened at-risk individuals for SARS-CoV-2 spike and nucleocapsid protein antibodies in a POC setting to determine if it was a feasible method to identify antibody from prior infection. Methods Three EUA-approved lateral flow antibody assays were performed on POC finger-stick blood and compared with serum and a CLIA nucleocapsid antibody immunoassay. Variables including antibody class, time since PCR, and the assay antigen used were evaluated. Results 512 subjects enrolled, of which 104 had a COVID-19 history and positive PCR. Only three PCR-positive subjects required hospitalization, with one requiring mechanical ventilation. The POC results correlated well with the immunoassay (93–97% sensitivity) and using serum did not improve the sensitivity or specificity. Conclusions Finger-stick, POC COVID-19 antibody testing was highly effective in identifying antibody resulting from prior infections in mildly symptomatic subjects. Using high-complexity serum immunoassays did not improve the screening outcome. Almost all individuals with COVID-19 infection produced detectable antibodies to the virus. POC antibody testing is useful as a screen for prior COVID-19 infection, and should be useful in assessing vaccine response.

scholarly journals Validation of dried blood spot sample modifications to two commercially available COVID-19 IgG antibody immunoassays

Bioanalysis ◽  
2020 ◽  
Author(s):  
Theodore T Zava ◽  
David T Zava
Keyword(s):  
Venous Blood ◽  
Dried Blood Spot ◽  
Blood Collection ◽  
Igg Antibodies ◽  
Antibody Testing ◽  
Igg Antibody ◽  
Nucleocapsid Proteins ◽  
Antibody Assays ◽  
Finger Stick ◽  
Blood Spot

Aim: Coronavirus disease 2019 antibody testing often relies on venous blood collection, which is labor-intensive, inconvenient and expensive compared with finger-stick capillary dried blood spot (DBS) collection. The purpose of our work was to determine if two commercially available anti-severe acute respiratory syndrome coronavirus 2 enzyme-linked immunosorbent assays for IgG antibodies against spike S1 subunit and nucleocapsid proteins could be validated for use with DBS. Materials & methods: Kit supplied reagents were used to extract DBS, and in-house DBS calibrators were included on every run. Results: Positive/negative concordance between DBS and serum was 100/99.3% for the spike S1 subunit assay and 100/98% for the nucleocapsid assay. Conclusion: Validation of the DBS Coronavirus disease 2019 IgG antibody assays demonstrated that serum and DBS can produce equivalent results with minimal kit modifications.

scholarly journals Pre-vaccination testing could expand coverage of two-dose COVID vaccines

2021 ◽  
Vol 6 ◽  
pp. 105
Author(s):  
Carl A. B. Pearson ◽  
Sam Clifford ◽  
Juliet R. C. Pulliam ◽  
Rosalind M. Eggo
Keyword(s):  
Vaccine Coverage ◽  
Point Of Care ◽  
Vaccine Dose ◽  
Cost Effective ◽  
Antibody Testing ◽  
Past Infection ◽  
Effective Manner ◽  
Highly Sensitive ◽  
Prior Infection ◽  
Antibody Tests

Recent evidence indicates that a single dose of mRNA-based vaccines produce similar immune responses in people with evidence of past infection compared with two doses in immunologically naive individuals. For COVID-19 vaccines with two dose regimens, point-of-care antibody testing for prior infection when administering the first dose could enable expanded vaccine access in a cost-effective manner. Generally, antibody tests with sensitivity and specificity well below that typically accepted for product licensure would still enable expanded vaccine coverage, though to be cost-beneficial total test cost (i.e. procurement and administration) needs to be less than roughly a third of total vaccine dose cost. For highly sensitive (90%) and specific (99%) tests, coverage could be expanded by more than 33%. Tests with the appropriate performance characteristics are plausible, though likely need setting specific tailoring.

scholarly journals Identification of natural SARS-CoV-2 infection in seroprevalence studies among vaccinated populations

2021 ◽  
Author(s):  
Ryan T Demmer ◽  
Brett Baumgartner ◽  
Talia D Wiggen ◽  
Angela K Ulrich ◽  
Ali J Strickland ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Nucleocapsid Protein ◽  
Natural Infection ◽  
Area Under The Curve ◽  
Self Report ◽  
Antibody Testing ◽  
Recent Infection ◽  
Discriminatory Ability ◽  
Antibody Assays ◽  
Protein Response

Importance: Identification of SARS-CoV-2 infection via antibody assays is important for monitoring natural infection rates. Most antibody assays cannot distinguish natural infection from vaccination. Objective: To assess the accuracy of a nucleocapsid-containing assay in identifying natural infection among vaccinated individuals. Design: A longitudinal cohort comprised of healthcare workers (HCW) in the Minneapolis/St. Paul metropolitan area was enrolled. Two rounds of seroprevalence studies separated by one month were conducted from 11/2020-1/2021. Capillary blood from round 1 and 2 was tested for IgG antibodies against SARS-CoV-2 spike proteins with a qualitative chemiluminescent ELISA (spike-only assay). In a subsample of participants (n=82) at round 2, a second assay was performed that measured IgGs reactive to SARS-CoV-2 nucleocapsid protein (nucleocapsid-containing assay). Round 1 biospecimen collections occurred prior to vaccination in all participants. Vaccination status at round 2 was determined via self-report. Setting: The Minneapolis/St. Paul, Minnesota metropolitan area. Participants: HCW age 18-80 years. Exposures: Round 1 recent SARS-CoV-2 infection assessed via a spike-only assay and participant self-report. Outcomes: Round 2 SARS-CoV-2 infection assessed via the nucleocapsid-containing assay. Area under the curve (AUC) was computed to determine the discriminatory ability of round 2 IgG reactivity to nucleocapsid for identification of recent infection determined during round 1. Results: Participants had a mean age of 40 (range=23-66) years, 83% were female, 46% reported vaccination prior to the round 2 testing. Round 1 seroprevalence was 9.5%. Among those not recently infected, when comparing vaccinated vs. unvaccinated individuals, elevated levels of spike 1 (p<0.001) and spike 2 (p=0.01) were observed while nucleocapsid levels were not statistically significantly different (p=0.90). Among all participants, nucleocapsid response predicted recent infection with an AUC(95%CI) of 0.93(0.88,0.99). Among individuals vaccinated >10 days prior to antibody testing, the specificity of the nucleocapsid-containing assay was 92% and while the specificity of the spike-only assay was 0%. Conclusions and Relevance: An IgG assay identifying reactivity to nucleocapsid protein is an accurate predictor of natural infection among vaccinated individuals while a spike-only assay performed poorly. In the era of SARS-CoV-2 vaccination, seroprevalence studies monitoring natural infection will require assays that do not rely on spike-protein response alone.

Antibody Screening Results for Anti-Nucleocapsid Antibodies Towards the Development of a SARS-CoV-2 Nucleocapsid Protein Antigen Detecting Lateral Flow Assay

2021 ◽  
Author(s):  
David Cate ◽  
Helen Hsieh ◽  
Veronika Glukhova ◽  
Joshua D Bishop ◽  
H Gleda Hermansky ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Point Of Care ◽  
Lateral Flow ◽  
Screening Methods ◽  
Antibody Screening ◽  
Liquid Handling ◽  
Large Numbers ◽  
Accurate Performance ◽  
Further Development ◽  
Assay Conditions

<p></p><p>The global COVID-19 pandemic has created an urgent demand for large numbers of inexpensive, accurate, rapid, point-of-care diagnostic tests. Analyte-based assays are suitably inexpensive and can be rapidly mass-produced, but for sufficiently accurate performance they require highly optimized antibodies and assay conditions. We used an automated liquid handling system, customized to handle arrays of lateral flow immunoassay (LFA) tests in a high-throughput screen, to identify anti-nucleocapsid antibodies that will perform optimally in an LFA. We tested 1021 anti-nucleocapsid antibody pairs as LFA capture and detection reagents with the goal of highlighting pairs that have the greatest affinity for unique epitopes of the nucleocapsid protein of SARS-CoV-2 within the LFA format. In contrast to traditional antibody screening methods (e.g., ELISA, bio-layer interferometry), the method described here integrates real-time reaction kinetics with transport in, and immobilization directly onto, nitrocellulose. We have identified several candidate antibody pairs that are suitable for further development of an LFA for SARS-CoV-2.</p><p></p>

scholarly journals Population (Antibody) Testing for COVID-19—Technical Challenges, Application and Relevance, an English Perspective

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 550
Author(s):  
Peter A. C. Maple
Keyword(s):  
National Level ◽  
Herd Immunity ◽  
Population Based ◽  
Biological Properties ◽  
Limited Extent ◽  
Antibody Testing ◽  
Serum Samples ◽  
Oral Fluids ◽  
Antibody Assays ◽  
The Uk

In the UK, population virus or antibody testing using virus swabs, serum samples, blood spots or oral fluids has been performed to a limited extent for several diseases including measles, mumps, rubella and hepatitis and HIV. The collection of population-based infection and immunity data is key to the monitoring of disease prevalence and assessing the effectiveness of interventions such as behavioural modifications and vaccination. In particular, the biological properties of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its interaction with the human host have presented several challenges towards the development of population-based immunity testing. Measuring SARS-CoV-2 immunity requires the development of antibody assays of acceptable sensitivity and specificity which are capable of accurately detecting seroprevalence and differentiating protection from non-protective responses. Now that anti-COVID-19 vaccines are becoming available there is a pressing need to measure vaccine efficacy and the development of herd immunity. The unprecedented impact of the SARS-CoV-2 pandemic in the UK in terms of morbidity, mortality, and economic and social disruption has mobilized a national scientific effort to learn more about this virus. In this article, the challenges of testing for SARS-CoV-2 infection, particularly in relation to population-based immunity testing, will be considered and examples given of relevant national level studies.

scholarly journals Does Point-Of-Care SARS-CoV-2 Antibody Testing Have Similar Sensitivity and Specificity To High Complexity Serology?

2021 ◽  
Vol 147 (2) ◽  
pp. AB77
Author(s):  
Kelly O'Shea ◽  
Charles Schuler ◽  
Jesse Chen ◽  
Carmen Gherasim ◽  
Donald Giacherio ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Point Of Care ◽  
High Complexity ◽  
Antibody Testing

scholarly journals Testing for SARS-CoV-2 seroprevalence: experiences of a tertiary eye centre

2021 ◽  
Vol 6 (1) ◽  
pp. e000688
Author(s):  
Focke Ziemssen ◽  
You-Shan Feng ◽  
Sven Schnichels ◽  
Tarek Bayyoud ◽  
Marius Ueffing ◽  
...  
Keyword(s):  
Point Of Care ◽  
Kappa Statistics ◽  
Antibody Testing ◽  
Self Assessment ◽  
Individual Assessment ◽  
Hygiene Measures ◽  
Antibody Titres ◽  
Antiviral Antibody ◽  
Sequential Combination ◽  
The Individual

IntroductionThe actual prevalence of a SARS-CoV-2 infection and the individual assessment of being or having been infected may differ. Facing the great uncertainty—especially at the beginning of the pandemic—and the possibility of asymptomatic or mildly symptomatic, subclinical infections, we evaluate the experience of SARS-CoV-2 antibody screening at a tertiary clinical setting.Methods and analysisAll employees of a tertiary eye centre and a research institute of ophthalmology were offered antibody testing in May 2020, using a sequential combination of different validated assays/antigens and point-of-care (POC) testing for a subset (NCT04446338). Before taking blood, a systematic inquiry into past symptoms, known contacts and a subjective self-assessment was documented. The correlations between serostatus, patient contacts and demographic characteristics were analysed. Different tests were compared by Kappa statistics.ResultsAmong 318 participants, SARS-CoV-2 antibodies were detected in 9 employees. Chemiluminescence assays (chemiluminescence immunoassay and electrochemiluminescence) showed superior specificity and high reproducibility, compared with ELISA and POC results.In contrast to the low seropositivity (2.8%) of healthcare workers, higher than that of the other departments of the hospital, a large proportion mistakenly assumed that they might have already been infected. Antiviral antibody titres increased and remained on a plateau for at least 3 months.ConclusionsThe great demand and acceptance confirmed the benefit of highly sensitive testing methods in the early phase of the pandemic. The coincidence of low seroprevalence and anxious employees may have contributed to internalising the need of hygiene measures.

scholarly journals The Laboratory Diagnosis of HIV Infections

2005 ◽  
Vol 16 (1) ◽  
pp. 26-30 ◽  
Author(s):  
Margaret Fearon
Keyword(s):  
Point Of Care ◽  
Diagnostic Testing ◽  
Clinical Information ◽  
Hiv Infections ◽  
Laboratory Diagnosis ◽  
The United States ◽  
Specific Information ◽  
Antibody Testing ◽  
Diagnostic Laboratory ◽  
Laboratory Results

HIV diagnostic testing has come a long way since its inception in the early 1980s. Current enzyme immunoassays are sensitive enough to detect antibody as early as one to two weeks after infection. A variety of other assays are essential to confirm positive antibody screens (Western blot, polymerase chain reaction [PCR]), provide an adjunct to antibody testing (p24 antigen, PCR), or provide additional information for the clinician treating HIV-positive patients (qualitative and quantitative PCR, and genotyping). Most diagnostic laboratories have complex testing algorithms to ensure accuracy of results and optimal use of laboratory resources. The choice of assays is guided by the initial screening results and the clinical information provided by the physician; both are integral to the laboratory's ability to provide an accurate laboratory diagnosis. Laboratories should also provide specific information on specimen collection, storage and transport so that specimen integrity is not compromised, thereby preserving the accuracy of laboratory results. Point of Care tests have become increasingly popular in the United States and some places in Canada over the past several years. These tests provide rapid, on-site HIV results in a format that is relatively easy for clinic staff to perform. However, the performance of these tests requires adherence to good laboratory quality control practices, as well as the backup of a licensed diagnostic laboratory to provide confirmation and resolution of positive or indeterminate results. Laboratory quality assurance programs and the participation in HIV proficiency testing programs are essential to ensure that diagnostic laboratories provide accurate, timely and clinically relevant laboratory results.

scholarly journals Universal PCR and antibody testing demonstrate little to no transmission of SARS-CoV-2 in a rural community

2020 ◽  
Author(s):  
Ayesha Appa ◽  
Saki Takahashi ◽  
Isabel Rodriguez-Barraquer ◽  
Gabriel Chamie ◽  
Aenor Sawyer ◽  
...  
Keyword(s):  
Rural Community ◽  
The United States ◽  
Rural Setting ◽  
Antibody Testing ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Rural Town ◽  
Low Prevalence ◽  
Prior Infection ◽  
Estimate Precision

Abstract Background Limited systematic surveillance for SARS-CoV-2 in the early months of the United States epidemic curtailed accurate appraisal of transmission intensity. Our objective was to perform case detection of an entire rural community to quantify SARS-CoV-2 transmission using PCR and antibody testing. Methods We conducted a cross-sectional survey of SARS-CoV-2 infection in the rural town of Bolinas, California (population 1,620), four weeks following shelter-in-place orders. Participants were tested between April 20 th – 24 th, 2020. Prevalence by PCR and seroprevalence from two forms of antibody testing were performed in parallel (Abbott ARCHITECT IgG and in-house IgG ELISA). Results Of 1,891 participants, 1,312 were confirmed Bolinas residents (&gt;80% community ascertainment). Zero participants were PCR positive. Assuming 80% sensitivity, it would have been unlikely to observe these results (p&lt;0.05) if there were &gt;3 active infections in the community. Based on antibody results, estimated prevalence of prior infection was 0.16% (95% CrI: 0.02%, 0.46%). The positive predictive value (PPV) of a positive result on both tests was 99.11% (95% CrI: 95.75%, 99.94%), compared to PPV 44.19%-63.32% (95% CrI range 3.25%-98.64%) if one test was utilized. Conclusions Four weeks following shelter-in-place, SARS-CoV-2 infection in a rural Northern California community was extremely rare. In this low prevalence setting, use of two antibody tests increased seroprevalence estimate precision. This was one of the first community-wide studies to successfully implement synchronous PCR and antibody testing, particularly in a rural setting. Widespread testing remains an underpinning of effective disease control in conjunction with consistent uptake of public health measures.

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