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Tag: testing
December 3, 2020
Pooled Saliva Specimens for SARS-CoV-2 Testing
A prospective study of pooled saliva specimens for RT-PCR testing for SARS-CoV-2 yielded lower sensitivity compared to nasopharyngeal (NP) or mid-turbinate (MT) swabs, but adequate detection in samples with high viral loads. Saliva specimens had 81.8% positive agreement with NP swabs, which rose to 90.0% positive agreement among samples with moderate to high viral load…
December 2, 2020
High Anal Swab Viral Load Predisposes Adverse Clinical Outcomes in Severe COVID-19 Patients
Higher viral load of SARS-CoV-2 RNA in anal swab samples was associated with severe COVID-19 outcomes including death (OR=1.4), ICU admission (OR=1.2) and need for invasive mechanical ventilation (OR=1.3) among a cohort of 188 hospitalized COVID-19 patients in China. The period from symptom onset to positive virus detection was also significantly shorter in non-survivors than…
December 1, 2020
Large-Scale Testing of Asymptomatic Healthcare Personnel for Severe Acute Respiratory Syndrome Coronavirus 2
Large-scale one-time testing of over 12,000 asymptomatic healthcare personnel (HCP) in the San Francisco Bay Area during April-June 2020 found low SARS-CoV-2 prevalence (0.2% by RT-PCR and 0.9% by serology tests). Most SARS-CoV-2-infected HCP were involved with direct patient care. One asymptomatic person with high viral load was identified, which, although rare, highlights the potential…
Serologic Testing of U.S. Blood Donations to Identify SARS-CoV-2-Reactive Antibodies: December 2019-January 2020
Analysis of archived samples from routine Red Cross blood donations collected December 13, 2019 to January 17, 2020 from donors in nine states, including Washington, suggests SARS-CoV-2 was introduced in the US prior to the first identified case in January 19, 2020. Among 7,389 samples, 106 contained antibodies reactive to the SARS-CoV-2 spike protein and…
November 30, 2020
Clinical Performance of the Point-of-Care Cobas Liat for Detection of SARS-CoV-2 in 20 Minutes: A Multicenter Study
A multi-site US study comparing the clinical performance of two cobas® RT-PCR tests, the Liat point of care test versus the most widely used test, the 68/8800 test, found that tests showed similar performance characteristics. The Liat test provides results in approximately 20 minutes. Overall agreement between the Liat and 68/8800 systems for SARS-CoV-2 diagnostics…
November 25, 2020
The Sensitivity of SARS-CoV-2 Antigen Tests in the View of Large-Scale Testing
A comparison of two point-of-care antigen tests to PCR testing concluded that the low sensitivity of antigen testing contributes to a significant risk of false negatives when used in symptomatic or asymptomatic COVID-19 patients. The two antigen tests exhibited sensitivities of 0.66 and 0.62 among all COVID-19 patients, 0.74 and 0.69 among symptomatic patients, and…
November 24, 2020
Catching a Resurgence Increase in SARS-CoV-2 Viral RNA Identified in Wastewater 48 Hours before COVID-19 Clinical Tests and 96 Hours before Hospitalizations
[Pre-print, not peer reviewed] Surveillance for SARS-CoV-2 at wastewater facilities in Ottawa identified resurgence of positive cases and hospitalizations in late July 2020 with a 48-hour and 96- hour lead time, respectively. When daily percent positivity was being reported below 1%, increases of >400% in normalized SARS-CoV-2 RNA signal in wastewater were identified 48 hours…
November 23, 2020
Pooling Is an Insufficient Strategy to Avoid Health Care Staff to Patient Transmission of SARS-CoV-2
Pooling strategies for SARS-CoV-2 RT-PCR screening showed low sensitivity compared to single sample testing in medical staff in a hospital in Germany. Among 280 samples tested (8 positive, 3%), the sensitivity was 29% in pooling with 10 samples (2/7 pools) and 76% in pooling with 5 samples (13/17 pools). In contrast to other studies, the…
A Serological Assay to Detect SARS-CoV-2 Antibodies in at-Home Collected Finger-Prick Dried Blood Spots
A home-based finger‐prick dried blood spot collection kit demonstrated 100% sensitivity and 100% specificity in detecting SARS-CoV-2 antibodies against S1 protein in 111 specimens collected at home from 31 patients with COVID-19 and 80 healthy participants. The authors conclude such methods may facilitate the test within hard-to reach-populations and help reduce the sample collection burden…
November 20, 2020
Multi-center nationwide comparison of seven serology assays reveals a SARS-CoV-2 non-responding seronegative subpopulation
Significant performance differences were observed in commercially available serologic assays for antibodies against SARS-CoV-2. In a multi-center clinical and analytical validation of seven commercially available automated serology assays, samples from 2391 SARS-CoV-2 negative individuals and 698 SARS-CoV-2 PCR positive patients (collected between March and May 2020) were analyzed. Significant performance differences were observed with major…
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