Expanding sampling options for COVID-19 could increase testing

Collecting tongue, nasal or mid-turbinate samples for SARS-CoV-2 testing, rather than nasopharyngeal samples, could help to identify infected individuals faster while reducing the risk of transmission to health care workers from potential droplets expressed during oropharynx or nasopharynx swabs. That’s according to correspondence published July 30, 2020, in The New England Journal of Medicine. The authors – from the University of Washington, Everett Clinic and Unitedhealth Group – obtained swab samples from the nasopharynx and at least one of the other sites in 530 patients with symptoms suggestive of upper respiratory infection. The patients were given instructions and asked to collect tongue, nasal and mid-turbinate samples, in that order. A health care worker then collected a nasopharyngeal sample. All of the swabs underwent reverse transcriptase polymerase chain reaction (RT-PCR) testing. “Of the 501 patients with both tongue and nasopharyngeal samples, both swabs tested negative in 450 patients, both swabs tested positive in 44, the nasopharyngeal swab was positive and the tongue swab was negative in 5, and the tongue swab was positive and the nasopharyngeal swab was negative in 2,” the authors wrote. The results were similar in patients with nasal and mid-turbinate samples. Overall, cycle threshold values from the RT-PCR tests showed Pearson correlations between the positive results of the nasopharyngeal samples and positive results of tongue, nasal and mid-turbinate samples of 9.48, 0.78 and 0.86, respectively. According to the authors, collecting samples for SARS-CoV-2 from locations other than the nasopharynx could “reduce PPE use and provide a more comfortable patient experience.”

Envisia classifier improves IPF diagnosis

Veracyte Inc. reported results from a new study showing its Envisia Genomic Classifier improves doctors’ ability to diagnose idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILD) without the need for surgery. Researchers from leading institutions in the U.S. and Europe, as well as from Veracyte, assessed the Envisia classifier’s ability to detect usual interstitial pneumonia (UIP), a key signature of IPF, in transbronchial biopsy samples collected from 96 patients being evaluated for possible ILD. The patients were part of multicenter BRAVE study in the U.S. and Europe. The Envisia classifier had specificity and sensitivity rates of 92.1% and 60.3%, respectively, in line with earlier clinical validation results. When used in conjunction with high-resolution computed tomography (HDCT) imaging, sensitivity for detecting UIP more than doubled, compared with HRCT alone (79.2% vs. 34%) and raised the diagnostic yield by more than 130%. The team suggested “recognition of a UIP pattern by the Envisia Genomic Classifier combined with HRCT and clinical factors in a multidisciplinary discussion may assist clinicians in making an ILD (especially IPF) diagnosis without the need for SLB.” Their work was published online July 30, 2020, in the American Journal of Respiratory and Critical Care Medicine.

Structural study gives insight into plaque formation

Investigators at the Sanford Burnham Prebys Medical Discovery Institute have gained new insights into how plaques form in a variety of different disorders, including dry age-related macular degeneration, which accounts for 90% of age-related macular degeneration cases and currently has no disease-modifying treatments. A major component of plaques is the blood protein vitronectin, and the researchers used biophysical techniques to show that vitronectin promoted plaque formation by simultaneously binding to soluble and a mineralized form of calcium phosphate called hydroxyapatite. The findings “provide a platform for understanding the pathogenesis of macular degeneration and other related degenerative disorders, and the normal functions of [vitronectin], especially those related to bone resorption,” the authors wrote. “The present findings … advance our understanding of the mechanisms of abnormal plaque formation and introduce a target with [the] potential for developing diagnostic, preventive, or therapeutic approaches.” Their work appeared in the July 20, 2020, online issue of the Proceedings of the National Academy of Sciences.

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