Covid-19: testing times

Beeching, Nick; Fletcher, Tom; Beadsworth, Mike

doi:10.1136/bmj.m1403

Cited by 206 publications

(223 citation statements)

References 10 publications

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“…The World Health Organization (WHO) has declared Covid-19 a pandemic, triggering various travel restrictions, border control, contact tracing, quarantine and social distancing measures in many countries (2). Despite these interventions, Covid-19 continues to spread, with 2 million cases reported globally (3), and even in countries with welldeveloped public health systems and aggressive implementation of measures (4). For instance, Singapore which reported its first imported case on 23 rd Jan 2020 and the first local transmission on 4 February 2020 (5,6), has seen a ten-fold increase in cumulative cases in the past 25 days (7).…”

Section: Introductionmentioning

confidence: 99%

“…(5). Diagnostic testing is recognized as a rate-limiting step, and there is a global need to ramp up laboratory capacity, in both well-developed and low-income countries (4,12). This is worsened by the possibility that asymptomatic individuals in the community could transmit infection, hence increasing the need to screen healthy individuals or those with mild symptoms (13)(14)(15).…”

Section: Introductionmentioning

confidence: 99%

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Rapid direct nucleic acid amplification test without RNA extraction for SARS-CoV-2 using a portable PCR thermocycler

Wee

Sivalingam

Yap

2020

Preprint

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There is an ongoing worldwide coronavirus disease 2019 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At present, confirmatory diagnosis is by reverse transcription polymerase chain reaction (RT-PCR), typically taking several hours and requiring a molecular laboratory to perform. There is an urgent need for rapid, simplified and cost-effective detection methods. We have developed and analytically validated a protocol for direct rapid extraction-free PCR (DIRECT-PCR) detection of SARS-CoV-2 without the need for nucleic acid purification. As few as 6 RNA copies per reaction of viral nucleocapsid (N) gene from respiratory samples such as sputum and nasal exudate can be detected directly using our one-step inhibitor-resistant assay. The performance of this assay was validated on a commercially available portable PCR thermocycler. Viral lysis, reverse transcription, amplification and detection are achieved in a single-tube homogeneous reaction within 36 minutes. This minimized hands-on time, reduces turnaround-time for sample-to-result and obviates the need for RNA purification reagents. It could enable wider use of Covid-19 testing for diagnosis, screening and research in countries and regions where laboratory capabilities are limiting.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rapid direct nucleic acid amplification test without RNA extraction for SARS-CoV-2 using a portable PCR thermocycler

Wee

Sivalingam

Yap

2020

Preprint

View full text Add to dashboard Cite

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“…Effective large-scale detection of the population is a favorable measure to identify the patients infected with COVID-19 [29,30]. Nevertheless, results from our study showed that the majority of the COVID-19 patients carry low viral loads in the upper respiratory tract, but a small population of them carry high viral loads.…”

Section: Discussionmentioning

confidence: 69%

A mild-symptom COVID-19 patient showed consistently high pharyngeal viral loads in a period of ten days after hospitalization

Chen¹,

Han

Sun³

et al. 2020

Preprint

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Background: The pandemics of coronavirus disease 2019 (COVID-19) threatens both human lives and health care system. COVID-19 patients may differ in their capability in spreading the causative virus, the severe acute respiratory syndrome-corona virus 2 (SARS-CoV-2). Methods: In this study, oropharyngeal swabs specimens from 43 patients admitted to our hospital during the COVID-19 peak time in Wuhan, China were obtained to survey temporal profiles of the viral loads in their upper respiratory tract. An internal and an absolute mRNA control were included in the real-time RT-PCR analysis and RNA extraction step to remove the potential influence of experimental variations on the result interpretation. Results: We found about one third of the hospitalized COVID-19 patients were never tested as SARS-CoV-2 positive during the course of this study. One patient with mild symptoms displayed constant high levels of viral loads after hospitalization, which were orders of magnitude higher than all other positive patients. Conclusions: We propose that if pharyngeal viral loads in a patient could indicate its ability in spreading the virus to others, then identification and strict separation of the high viral load patients should provide an effective mean in restricting viral spreading and protect health care workers from infection.

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Section: Introductionmentioning

confidence: 99%

“…Due to the high virus spread rate it is necessary tests for diagnosis that are quick and precise [5]. The precise diagnosis in patients with Covid-19 permit they receive due medical attention, furthermore placing these patients in isolation will decrease the disease spread [5]. The test standard to the Covid-19 diagnosis is the quantitative polymerase chain reaction (qPCR), however this exam needs several hours to confirm positivity [20].…”

Section: Introductionmentioning

confidence: 99%

IKONOS: An intelligent tool to support diagnosis of Covid-19 by texture analysis of x-ray images

Gomes

Barbosa

Santana

et al. 2020

Preprint

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In late 2019, the SARS-Cov-2 spread worldwide. The virus has high rates of proliferation and causes severe respiratory symptoms, such as pneumonia. There is still no specific treatment and diagnosis for the disease. The standard diagnostic method for pneumonia is chest X-ray image. There are many advantages to using Covid-19 diagnostic X-rays: low cost, fast and widely available. We propose an intelligent system to support diagnosis by X-ray images. We tested Haralick and Zernike moments for feature extraction. Experiments with classic classifiers were done. Support vector machines stood out, reaching an average accuracy of 89.78%, average recall and sensitivity of 0.8979, and average precision and specificity of 0.8985 and 0.9963 respectively. The system is able to differentiate Covid-19 from viral and bacterial pneumonia, with low computational cost.

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Covid-19: testing times

Abstract: Rapid near patient testing for both current and past infections is urgently required

Cited by 206 publications

References 10 publications

Rapid direct nucleic acid amplification test without RNA extraction for SARS-CoV-2 using a portable PCR thermocycler

Rapid direct nucleic acid amplification test without RNA extraction for SARS-CoV-2 using a portable PCR thermocycler

A mild-symptom COVID-19 patient showed consistently high pharyngeal viral loads in a period of ten days after hospitalization

IKONOS: An intelligent tool to support diagnosis of Covid-19 by texture analysis of x-ray images

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