Result for
Tag: testing
October 22, 2020
Is “No Test Is Better than a Bad Test”? Impact of Diagnostic Uncertainty in Mass Testing on the Spread of COVID-19
Gray et al. suggest that tests for SARS-CoV-2 with poor sensitivity and specificity could be potentially worse than not implementing tests at all in a model-based analysis. The model scenarios include no lockdown, immunity passports, and incremental relaxation. Tests, even if highly sensitive, are not sufficient to prevent widespread infection in the no lockdown scenario….
October 21, 2020
Multiplex Rt-Real Time PCR Assays for Diagnostic Testing of SARS-CoV-2 and Seasonal Influenza Viruses
A multiplex RT-PCR assay was able to detect and discriminate between samples that were positive for SARS-CoV-2 and influenza and was able to detect co-infections. The authors suggest that the assay may be used for diagnostic and surveillance purposes during the seasonal influenza activity period. Mancini et al. (Oct 20, 2020). Multiplex Rt-Real Time PCR…
Quantitative Assessment of Olfactory Dysfunction Accurately Detects Asymptomatic COVID-19 Carriers
A novel design of an olfactory-action meter, which measures how well a person smells odors, found that 82% of asymptomatic SARS-CoV-2 carriers (n=34) had olfactory deficits, compared to 13% of health volunteers. By comparison, only 15% of asymptomatic carriers had olfactory deficits detected by subjective evaluation. This method evaluated a combination of olfactory detection abilities…
October 20, 2020
Pooling of Samples to Optimize SARS-CoV-2 Diagnosis by RT-QPCR: Comparative Analysis of Two Protocols
Pooling naso- or oropharyngeal swab samples prior to RNA extraction was associated with 100% diagnostic accuracy, while pooling after individual-sample RNA extraction was associated with 91% diagnostic accuracy. Volpato et al. conclude that testing protocols should call for pooling swab samples before RNA extraction. Volpato et al. (Oct 16, 2020). Pooling of Samples to Optimize…
October 19, 2020
Weak Correlation between Antibody Titers and Neutralizing Activity in Sera from SARS‐CoV‐2 Infected Subjects
Criscuolo et al. found a poor direct correlation between anti-SARS-CoV-2 antibody titers and neutralizing activity levels against a clinical isolate of SARS-CoV-2. The authors suggest these findings highlight a need for future investigations into the role of neutralizing antibodies and their correlation with protection. In keeping with earlier studies, two commercial serology tests by DiaSorin…
Association of Time to Diagnosis with Socioeconomic Position and Geographical Accessibility to Healthcare among Symptomatic COVID-19 Patients: A Retrospective Study in Hong Kong
Living in public rental houses and living in an area with low educational attainment were associated with longer time to diagnosis in the first wave of SARS-CoV-2 infections in Hong Kong. In contrast, this association was not observed during the second wave of infections, when the surveillance measures were enhanced. The study examined socioeconomic characteristics…
October 16, 2020
Capillary Whole-Blood IgG-IgM COVID-19 Self-Test as a Serological Screening Tool for SARS-CoV-2 Infection Adapted to the General Public
Observations from a cross-sectional, general adult population pilot study in France indicated high practicability and satisfaction of SARS-CoV-2 IgG-IgM self-testing using the Exacto COVID-19 self-test. The study used a variety of questionnaires to determine if participants could both use the test and interpret its results correctly. All 167 participants correctly used the self-test, although 12 asked…
October 14, 2020
Risk Factors for Re-Detectable Positivity in Recovered COVID-19 Children
In a healthcare setting in China where two negative PCR tests for SARS-Cov-2 were required for hospital discharge, 37% of pediatric patients (n=14) had positive PCR tests upon subsequent PCR testing (“re-detectable positivity”). Family cluster infection, higher white blood cell count, and longer plasma prothrombin time were identified as risk factors for re-detectable positivity. In…
Evaluation of Saliva Sampling Procedures for SARS-CoV-2 Diagnostics Reveals Differential Sensitivity and Association with Viral Load
[Preprint, not peer-reviewed] Saliva collection devices showed poor sensitivities for detecting SARS-CoV-2 RNA in Belgian outpatients. Saliva samples collected either by spitting into a commercial preservative (Norgen Biotek) or swabbing (DNA Genotek) had sensitivities of 31% and 22% when compared to individuals who were PCR-positive on nasopharyngeal swabs (N=107) from outpatient triage centers in Belgium….
October 12, 2020
Sample Pooling Is a Viable Strategy for SARS-CoV-2 Detection in Low-Prevalence Settings
Sample pooling was found to be a practical strategy for SARS-CoV-2 testing in low-prevalence settings. The study assessed the sensitivity and theoretical efficiency of two, four, and eight-sample pools to evaluate throughput and assess the potential to conserve PCR reagents. As pool size increased, sensitivity decreased and efficiency increased. The practicality of pooling samples also…
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