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Accuracy Variability In COVID-19 Antibody Tests, Other News

July 16, 2020 | A new peer-reviewed study by researchers at NSF International and Novateur Ventures finds significant variability in the accuracy of currently available COVID-19 antibody tests. This, plus more, are included in this week’s COVID-19 news and research in the diagnostics industry.

Literature Updates

A new peer-reviewed study by researchers at NSF International and Novateur Ventures finds significant variability in the accuracy of currently available COVID-19 antibody tests. The study, "COVID-19 Serological Tests: How Well Do They Actually Perform?", appears in the latest issue of the journal Diagnostics. Published independent performance data of five CLIA (chemiluminescence immunoassay), 15 ELISA (enzyme-linked immunosorbent assay) and 42 RDT (rapid diagnostic test) antibody tests that are currently on the market were reviewed for this study to understand their limits and potential. The findings show significant variability in the accuracy of marketed tests and highlight several lab-based and point-of-care rapid diagnostic tests with high performance levels in detecting SARS-CoV-2 specific antibodies. The findings of this review highlight the need for ongoing independent evaluations of commercialized COVID-19 diagnostic tests. DOI: 10.3390/diagnostics10070453

Pharmacists at Martin Luther University Halle-Wittenberg (MLU) have succeeded in detecting small amounts of coronavirus SARS-CoV-2 using mass spectrometry of gargle solutions of COVID-19 patients. Initial results have been publishe d in the Journal of Proteome Research. The protocol consists of an acetone precipitation and tryptic digestion of proteins contained within the gargle solution, followed by a targeted MS analysis. The methodology identifies unique peptides originating from SARS-CoV-2 nucleoprotein. Building on these promising initial results, faster MS protocols can now be developed as routine diagnostic tools for COVID-19 patients, the authors write. DOI: 10.1021/acs.jproteome.0c00280

Researchers from Johns Hopkins University conducted universal SARS-CoV-2 testing of 11 long-term care facilities in Maryland. The published their findings in JAMA Internal Medicine. Of the 893 residents who had not been previously diagnosed, 354 tested positive. Of those, 281 (55.4%) were asymptomatic. The researchers followed up on the residents of seven of the facilities two weeks later. Of the 177 positive cases, 154 had been asymptomatic at the time of testing. Of the symptomatic residents, 4 were hospitalized and 2 had died within 14 days. Of the asymptomatic patients, 20 were hospitalized and 7 had died within 14 days. DOI: 10.1001/jamainternmed.2020.3738.

In a retrospective study of 205 COVID-19 patients, investigators from New York University Langone Health found that the quantity of SARS-CoV-2 (viral load) collected from patients in the emergency department is significantly higher in patients with fewer or milder symptoms who did not require hospitalization—the opposite of what might be expected. Reporting in The American Journal of Pathology, they found that the initial viral load was significantly lower in patients who required hospitalization compared to those who were discharged. The association remained significant even after adjustment for age, sex, race, body mass index, and other existing medical conditions. They also found that a higher viral load was associated with shorter duration of symptoms in all patients and was not associated with disease severity. DOI: 10.1016/j.ajpath.2020.07.001

An open-access American Journal of Roentgenology (AJR) article investigating the differences in CT findings between coronavirus disease (COVID-19) pneumonia and influenza virus pneumonia found that most lesions from COVID-19 were located in the peripheral zone and close to the pleura, whereas influenza virus was more prone to show mucoid impaction and pleural effusion, though differentiating is still difficult. A total of 97 patients (49 women, 48 men) were enrolled in this study. Of them, 52 patients (29 men, 23 women; age range, 21-73 years) had COVID-19 pneumonia; 45 patients (26 women, 19 men; age range, 15-76 years) had influenza virus pneumonia (28, influenza A; 17, influenza B). All patients had positive nucleic acid testing results for the respective viruses, as well as complete clinical data and CT images. Between the group of patients with COVID-19 pneumonia and the group of patients with influenza virus pneumonia, the largest lesion close to the pleura (i.e., no pulmonary parenchyma between the lesion and the pleura), mucoid impaction, presence of pleural effusion, and axial distribution showed statistical difference (p < 0.05). But the authors observed no significant difference (p > 0.05) in CT score, length of the largest lesion, mean density, volume, or mass of the lesions between the two groups. DOI: 10.2214/AJR.20.23304

Results of a retrospective analysis published in the Annals of the American Thoracic Society found that Black individuals were twice as likely as White individuals to test positive for COVID-19. Of the 4413 individuals tested at the University of Chicago between January 1 and April 15, 17.8% tested positive for COVID-19. Of those who tested positive, 78.9% were Black while 9.6% were White. These data suggest that Blacks are more likely to test positive and be hospitalized with SARS-CoV-2; however, we found no difference in mortality for Blacks vs non-Blacks, the authors wrote. “Possible hypotheses for these disproportionally high rates among Blacks include disparities in predisposing medical conditions, health insurance status, and access to medical care.” DOI: 10.1513/AnnalsATS.202006-583RL

Researchers conducted an online experiment with 371 participants who viewed a COVID-19 screening session between a hotline agent—chatbot or human—and a user with mild or severe symptoms. They studied whether the participants believed the chatbots were persuasive, providing satisfying information that likely would be followed. Their results showed a slight negative bias against chatbots' ability, but when the perceived ability is the same, participants reported that they viewed chatbots more positively than human agents. The key is to emphasize the chatbot’s ability and assure users that it delivers the same quality as human agents, the researchers said. DOI:10.1093/jamia/ocaa167

Industry Updates

Quantabio’s UltraPlex 1-Step ToughMix was recognized as part of the new emergency use authorization (EUA) for the Centers for Disease Control and Prevention (CDC) Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay. The Flu SC2 Assay is a real-time, reverse transcription quantitative PCR (RT-qPCR) test that aids in the detection and differentiation of RNA from the similar SARS-CoV-2, influenza A and/or influenza B viruses. Qualified high-complexity, CLIA-certified laboratories are now advised to use the UltraPlex 1-Step ToughMix, as one of two validated master mixes, to ensure robust and reliable performance of multiplexed RNA detection assays that may have a wide range of inhibitory starting materials. Press release.

BD (Becton, Dickinson and Company), a leading global medical technology company, announced today a commitment from the U.S. Department of Health and Human Services (HHS) to purchase BD diagnostic solutions in expanding access to rapid point-of-care testing for COVID-19 through a broad, decentralized network of testing instrumentation. HHS has committed to purchase 2,000 BD Veritor Plus Systems and 750,000 SARS-CoV-2 antigen test kits for use on the system. Distribution is set to begin next week. Press release.

Through a new collaboration, the State of Arizona and Arizona Department of Health Services are providing Sonora Quest Laboratories $2 million toward the purchase of new processing equipment to expand COVID-19 testing in Arizona. Sonora Quest is contributing an additional $6 million in order to reach the capacity to perform up to 35,000 diagnostic tests per day by the end of July, and up to 60,000 tests per day by the end of August. The new production lines will include chemagic 360 instruments, JANUS G3 Primary Sample Reformatters and PCR+ Workstations, to automate PerkinElmer’s RNA extraction and RT-PCR testing. The breadth of PerkinElmer’s total workflow solutions will enable Sonora Quest to rapidly process samples at higher volumes, ultimately helping decrease turnaround time in testing. Press release.

New England Biolabs (NEB) has launched the SARS-CoV-2 Rapid Colorimetric LAMP Assay Kit, a Research Use Only (RUO) product that can be used for the detection of novel coronavirus, SARS-CoV-2 RNA. The kit serves as a simple alternative to RT-qPCR and enables visual detection of amplification of SARS-CoV-2 nucleic acid in just 30 minutes. The kit utilizes loop-mediated isothermal amplification (LAMP) to detect specific segments of the viral genome. This system provides a clear visual detection of amplification, based on the generation of protons and the subsequent drop in pH that occurs from the extensive DNA polymerase activity in a LAMP reaction. The decrease in pH produces a color change, with pink indicating a negative result and yellow indicating a positive result. Press release.

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