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Tag: testing
December 17, 2020
Health Center Testing for SARS-CoV-2 During the COVID-19 Pandemic — United States, June 5–October 2, 2020
Patient data from Health Resources and Services Administration (HRSA)-funded health centers found higher testing rates among members of racial/ethnic minority groups, indicating a degree of success in the health centers’ capacity to reach minority groups at increased risk for COVID-19. Among persons with known race/ethnicity who received testing (n=2,506,935), 36% were Hispanic/Latino, 38% were white,…
The Accuracy of Healthcare Worker versus Self Collected (2-in-1) Oropharyngeal and Bilateral Mid-Turbinate (OPMT) Swabs and Saliva Samples for SARS-CoV-2
A diagnostic accuracy study (n=401 patients with confirmed COVID-19 diagnosis) found that self-collected oropharynx and mid-turbinate (OMPT) and saliva samples had lower detection rates (75.1% and 74.3%, respectively) than healthcare worker (HCW)-collected OPMT swabs (82.8%). However, the combination of self-collected OMPT and saliva samples performed similarly (86.5% detection rate). The sensitivity of self-collected samples increased…
December 14, 2020
Impact of Mass Testing during an Epidemic Rebound of SARS-CoV-2 A Modelling Study
[Preprint, not peer-reviewed] A modeling study using a compartmental SEEIR model to evaluate the impact of mass testing of SARS-CoV-2 during an epidemic rebound in France found that a monthly campaign covering 75% of the population would reduce daily infections by 43% by May 1st, 2021, and a bi-weekly campaign would reduce infections by 75%….
December 11, 2020
Multicenter Evaluation of the Clinical Performance and the Neutralizing Antibody Activity Prediction Properties of ten high throughput serological assays used in Clinical Laboratories
In a study evaluating ten enzyme immunoassays and three lateral flow chromatography assays, seven immunoassays were shown to have excellent specificity (98 to 100%) and good to excellent positive predictive values (82 to 100%) when used in a low (5%) seroprevalence setting. Sensitivity values as low as 74% and as high as 95% at ≥15…
Comparison of Estimated SARS-CoV-2 Seroprevalence through Commercial Laboratory Residual Sera Testing and a Community Survey
Estimates of seroprevalence of antibodies against SARS-CoV-2 among residents of metropolitan Atlanta during April-May 2020 ranged from 4.9% to 3.2%. These estimates were based on antibody tests conducted on residual sera from commercial laboratory samples (4.9% seroprevalence) and a community household survey (3.2% seroprevalence). Compared with more representative surveys, the authors conclude that that commercial…
False-negative results of initial RT-PCR assays for COVID-19: A systematic review
A systematic review of 34 studies (12,057 patients) on detection of SARS-CoV-2 by RT-PCR assays at first use estimated a false-negative rate of 13% (95% CI 9% to 19%), though identified substantial heterogeneity between studies, which ranged in their individual estimates from 1.8% to 58%. The authors were unable to investigate most potential sources of…
December 10, 2020
Multi-Center Evaluation of the Cepheid Xpert® Xpress SARS-CoV-2/Flu/RSV Test
Evaluation of the Xpert Xpress SARS-CoV-2/Flu/RSV panel test showed high sensitivity and accuracy to distinguish SARS-CoV-2 from influenza and respiratory syncytial virus (RSV). Among 319 nasopharyngeal swab specimens (n=228 positive for SARS-CoV-2, influenza, or RSV; n=91 negative for all 3 infections), positive agreement for SARS-CoV-2 was 98.7% (n=74/75) and negative agreement was 100% (n=91), while…
December 4, 2020
Identification of Presymptomatic and Asymptomatic Cases Using Cohort-Based Testing Approaches at a Large Correctional Facility – Chicago, Illinois, USA, May 2020
Cohort-based SARS-CoV-2 testing among detained persons in a Chicago jail who had been exposed to individuals with laboratory-confirmed infection found that the approach identified infected individuals who would not have be detected by symptom screening, with more than half of newly-identified cases either presymptomatic or asymptomatic. Two testing strategies were evaluated, the first involved serial…
December 3, 2020
Increased Intensity Of PCR Testing Reduced COVID-19 Transmission Within Countries During The First Pandemic Wave
A study across 173 countries and territories representing 99% of global COVID-19 cases concluded that among COVID-19 interventions, PCR testing had the greatest association with reducing the average reproduction number (R0). Though testing intensity showed the largest variation among all interventions, a ten-fold increase in the ratio of tests to new cases reduced the R0…
Simple Questionnaires to Improve Pooling Strategies for SARS-CoV-2 Laboratory Testing
Questionnaire-based risk stratification could further enhance the efficiency of pooling strategies for SARS-CoV-2 lab testing. Schneitler et al. pooled samples using responses to a short questionnaire about clinical symptoms, travel history, and contact with people with confirmed COVID-19. In a sample (n=25,978) with overall SARS-CoV-2 prevalence of 0.9%, randomly pooled samples had higher pool positivity…
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