Date Published: April 24, 2020
Publisher: F1000 Research Limited
Author(s): Gerald Mboowa.
On March 11, 2020 the World Health Organization (WHO) upgraded the status of the coronavirus disease 2019 (COVID-19) outbreak from epidemic to a global pandemic. This infection is caused by a novel coronavirus, SARS-CoV-2. Several rapid diagnostic tests have been developed at an astonishing pace; however, COVID-19 requires more highly specific rapid point-of-care diagnostic tests. This review describes the currently available testing approaches, as well as the available test assays including the Xpert® Xpress SARS-CoV-2 test (takes
~45 min) and Abbott ID COVID-19 test (5 min) as easy to use point-of-care tests for diagnosis of novel COVID-19 that have so far received the US Food and Drug Administration emergency use authorizations clearance. This review is correct as of the date published and will be updated as more diagnostic tests come to light.
Infectious diseases are still a major threat in the world today
1. The diagnosis and real-time tracking of both emerging
2 and re-emerging infectious diseases must be reliable, fast, and affordable. Healthcare systems use different approaches to make infectious diseases diagnoses, such as clinical assessment (signs and symptoms), microscopy, microbiological cultures, radiology, molecular techniques – classical or real-time polymerase chain reaction (PCR), genome sequencing (detection presence of nucleic acid), serology (detection of the pathogens or host antibodies), artificial intelligence and machine learning
3. In modern medical diagnostics, whole or targeted genome sequencing or detection technologies are indispensable. In the event of novel pathogens, such as coronavirus, these technologies offer the shortest turnaround time (TAT) for results to be reported. Coupling comprehensive clinical evaluation, triaging, genomic-based diagnostics, and epidemiology to innovative digital disease detection raises the possibility of an open, global, pathogen surveillance system.
The manifestation of the COVID-19 infection is highly nonspecific and presents respiratory symptoms, fever, cough, dyspnoea, and viral pneumonia
7. Thus, diagnostic tests specific to this infection are urgently required to confirm suspected cases, screen patients, and conduct virus surveillance. In this scenario, a rapid, robust, and cost-efficient device that can be used anywhere and which does not necessarily require a trained technician to operate
8 (i.e. at point-of-care) is crucial and urgently needed for the detection of COVID-19
9. Several assays that detect SARS-CoV-2
have been developed so far, including Rapid IgM-IgG Combined Antibody Test For Coronavirus (RayBiotech Life), 2019-nCoV IgG/IgM Antibody Detection Kit (MyBioSource, Inc.), qSARS-CoV-2 IgG/IgM Rapid Test (Cellex, Inc.), ARIES SARS-CoV-2 Assay (Luminex Corporation), SGTi-flex COVID-19 IgM/IgG (Sugentech, Inc), while still under development is the ultrasensitive, rapid, portable coronavirus SARS-CoV-2 nucleic acid sequence detection system that uses nanobiosensor-based aptamer technology
10 are currently under development. These are both
commercially available. Some assays detect only the novel form of virus and some may also detect other viral strains (e.g. SARS-CoV) that are genetically similar to SARS-CoV-2
11. More about status of evaluation of SARS-COV-2 molecular diagnostics tests can be found
here. This includes the viral molecular target utilised in the test, country of manufacturer and its regulatory status.
Emerging and re-emerging pathogens are global challenges for public health
13. Laboratory biosafety requirements related to COVID-19 virus include the availability of biosafety requirements for viral cultures and further manipulations. The World Health Organisation (WHO) recommends that all procedures must be performed based on risk assessment and only by highly trained personnel with demonstrated capability in strict observance to all relevant protocols at all times
14. Non-propagative diagnostic laboratory work, such as viral genome sequencing and nucleic acid amplification tests, must be conducted at containment facilities and procedures equivalent to biosafety level 2 (BSL-2) while propagative work that involves coronavirus culture, isolation, animal inoculation or neutralization assays must be done at a high-biocontainment laboratory with inward directional airflow (minimum BSL-3)
14. Viral cultures are not recommended for routine diagnosis and must be carried in a minimum of BSL-3 facility or BSL-4
14. However, SARS-COV-2 virus isolation in cell cultures is critical to obtain isolates for characterization and to support the development of vaccines, therapeutic agents
15 and new or better diagnostic tests.
Point-of-care testing means that results are delivered to patients in the patient care setting, such as hospitals, urgent care centers and medical emergency rooms, instead of samples being sent to a testing laboratory. Real-time PCR, also known as quantitative PCR, is commonly used in molecular point-of-care testing. It can amplify more than one genomic target and in the case of COVID-19 and these can be
ORF1ab of coronaviruses occupy about two thirds of their genomes. It encodes the replicase polyprotein and is translated from ORF1a and ORF1b,
E-gene (envelope protein) and
N-gene (the nucleocapsid protein)
21 and RNA-dependent RNA polymerase (RdRp) that is an essential viral enzyme, which replicates positive-strand RNA viral genome. For more specificity, some molecular diagnostic assays amplify more than one molecular target in the virus to minimize chances of all three targets mutating and hence being missed by the diagnostic test
21. During the development of disease testing assays, US manufacturers can apply for emergency clinical use authorization from FDA, and in the European Union manufacturers can obtain “Conformité Européene” which literally means “European Conformity”, marking them for
in vitro diagnostic use.
Following the emergence of SARS-CoV-2, genomic analyses continue to play a key role in the public health response by informing the design of appropriate molecular diagnostics and corroborating epidemiological efforts to trace contacts
35. In order to better understand the spread of this pandemic and design better interventions, whole genome sequencing of the virus from a range of clinical presentations of the disease in different parts of the world must occur (
Figure 1). It has been suggested from rapid data sharing using publicly available sequence data platforms that this pandemic was a point-source outbreak
36. Therefore, researchers need more data from the whole genomes of SARS-CoV-2 including viral transcriptome
37. All these have the potential to reveal further insights into the biology of this emergent pathogen
35. Nanopore MinION sequencing technology has been used to sequence SARS-CoV-2 genomes
39. Many of these genomes have been successfully uploaded to Global Initiative on Sharing All Influenza Data –
GISAID by the WHO reference laboratories globally and
Nextstrain. Other public repositories that have a number of these sequences are GenBank and the Sequence Read Archive of the US National Center for Biotechnology.
Currently with more than 2.6 million infected individuals in 185 sovereign states and 183,000 deaths globally
40 at the time of writing, the COVID-19 pandemic may see deployment of COVID-19 rapid non-invasive point-of-care tests at civil airports and national borders to screen individuals and avoid imported cases of the infection. This would be similar to mitigation of aircraft hijackings and in-flight sabotage using mandatory civil aviation security procedures, including strict security screening for passengers and baggage at all commercial airports
41. Currently, screening for COVID-19 is performed by checking for high fever in individuals coming through airports and border controls using thermal screening guns. A nanosensor diagnostic platform is in development to test for this virus, which will replace thermal screening guns and be more specific. This technology, which will be in the form of a hand-held device, promises to give results specific for this virus within one minute, by detecting the nucleocapsid protein specific for this virus using nanosensor and aptamer technology
To minimise the current COVID-19 pandemic related pressure on health systems globally, especially arising from ramping up testing capacity quickly, readily accessible, cheap, easy to use and interpret point-of-care diagnostic tests with high sensitivity must be developed, produced and distributed widely.
No data is associated with this article.