COVID-19 research briefs: self-collected swabs accurate for detection; fever, cough, elevated CRP common in COVID-19

Daily POEMs

Published: 2020-07-12 © 2020 John Wiley & Sons, Inc.

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Clinical question
Can patient-collected swabs accurately detect the presence of SARS-CoV-2? What symptoms and laboratory findings are common in patients with COVID-19?

Bottom line
Self-collected swabs are accurate in detecting SARS-CoV-2 in ambulatory settings. Fever, cough, elevated C-reactive protein levels, and ground glass opacities are common in patients with COVID-19 in China. (LOE = 2c)

Reference
Tu YP, Jennings R, Hart B, et al. Swabs collected by patients or health care workers for SARS-CoV-2 Testing. N Engl J Med. Published online June 3, 2020. doi: 10.1056/NEJMc2016321 Fu L, Wang B, Yuan T, et al. Clinical characteristics of coronavirus disease 2019 (COVID-19) in China: A systematic review and meta-analysis. J Infect 2020;80(6):656-665.

Study design: Other

Setting: Other

Synopsis
Research Brief #38: These researchers in the United States identified 530 symptomatic COVID-19 patients seen in ambulatory clinics in the Puget Sound area of Washington. After brief training, the patients were asked to collect tongue, nasal (inserted vertically into the nasal passage), and mid-turbinate (inserted horizontally into the nasal passage) samples, in that order. After the self-sampling, trained staff collected swab samples from the nasopharynx. The authors estimated that this study would need to have 48 patients with a positive result for SARS-CoV-2 to have adequate power. Not surprisingly, most of the time patients tested positive at more than one site, regardless of who gathered the sample. Using the staff-collected sample as "the gold standard," the authors determined that self-collected samples were 89.8% sensitive (one-sided 97.5% confidence interval [CI] 78.2 - 100.0) for tongue samples, 94.0% sensitive (83.8 - 100.0) for nasal samples, and 96.2% sensitive (87.0 - 100.0) for mid-turbinate samples. This study suggests that patient-collected samples are reasonably accurate and have the potential to decrease the frequency of exposing staff to potentially infectious material. Tu YP, Jennings R, Hart B, et al. Swabs collected by patients or health care workers for SARS-CoV-2 Testing. N Engl J Med. Published online June 3, 2020. doi: 10.1056/NEJMc2016321. Research Brief #39: These authors conducted a systematic review and identified 43 studies with 3600 patients with COVID-19 in China. They excluded studies that took place outside of mainland China. They extracted and summarized the frequency of symptoms and laboratory and radiographic findings. They found substantial variability in the data, as well as significant publication bias. Only nine of the studies were at low risk of bias and 30 were of moderate risk of bias. Among the symptoms reported, the most common include: fever (83%), cough (60%), and fatigue (38%), followed by myalgias (29%) and dyspnea (25%). In addition, 8% had diarrhea; other studies have shown a significantly higher risk of transmission among patients with diarrhea. The following laboratory findings were also commonly elevated: C-reactive protein (68.6%), lactate dehydrogenase (51.6%), and D-dimer (29.3%). Finally, 80% of patients had x-ray findings of ground glass opacities, and 73.2% had bilateral pneumonia. Fu L, Wang B, Yuan T, et al. Clinical characteristics of coronavirus disease 2019 (COVID-19) in China: A systematic review and meta-analysis. J Infect 2020;80(6):656-665.

Henry C. Barry, MD, MS
Professor
Michigan State University
East Lansing, MI

Copyright © 2020 John Wiley & Sons, Inc.