Diagnostic approaches in COVID-19: clinical updates

ABSTRACT

Introduction

COVID-19 is a recent emerging pandemic whose prognosis is still unclear. Diagnostic tools are the main players that not only indicate a possible infection but can further restrict the transmission and can determine the extent to which disease progression would occur.

Areas covered

In this paper, we have performed a narrative and critical review on different technology-based diagnostic strategies such as molecular approaches including real-time reverse transcriptase PCR, serological testing through enzyme-linked immunosorbent assay, laboratory and point of care devices, radiology-based detection through computed tomography and chest X-ray, and viral cell cultures on Vero E6 cell lines are discussed in detail to address COVID-19. This review further provides an overview of emergency use authorized immunodiagnostic and molecular diagnostic kits and POC devices by FDA for timely and efficient conduction of diagnostic tests. The majority of the literature cited in this paper is collected from guidelines on protocols and other considerations on diagnostic strategies of COVID-19 issued by WHO, CDC, and FDA under emergency authorization.

Expert opinion

Such information holds importance to the health professionals in conducting error-free diagnostic tests and researches in producing better clinical strategies by addressing the limitations associated with the available methods.

KEYWORDS:

• COVID-19
• SARS-CoV-2
• immunodiagnostics
• point of care
• serological testing
• radiology
• viral cell culture
• rRT-PCR

Article highlights

• Coronavirus are positive sense single stranded RNA viruses enveloped in nature. A total of three viral outbreak happened in humans, one of them is a recent novel strain, SARS-CoV-2. Higher transmission rate has resulted in its spread to 213 countries causing a major impact on their socio-economic status.

• The virus is known to cause acute lung injuries and pneumonia. People with existing comorbidities and higher age are at increased risk of catching the viral infection. There are 12.8 million confirmed cases and 0.5 million deaths across the globe so far.

• Different technology based tests such as molecular, serological, radiological, and microbiological techniques are currently being employed for faster and efficient testing of the virus.

• rRT-PCR based molecular diagnosis is considered as one of the best approach in diagnosing the infection that aims to identify the genetic sequence of the viral genome however; each time a highly professional approach is required for interpretation of the results. Different viral proteins can be targeted for the identification purpose including N, E, S, RdRP, and ORF 1ab.

• Serological tests such as ELISA, chemiluminescent assay, and neutralization assay are followed on the principles of antigen antibody detection and various rapid diagnostic tests are made as an advancement in diagnosis.

• Radiological detection through use of chest-X-ray (CXR) and computed tomography scan (CT) aids in studying the COVID-19 affected lung lessions but the varied results obtained under different stages and condition of infection, suggests the diagnosis to be performed by combining molecular and radiological testing together.

• U.S. Food and Drug Administration (FDA) has provided emergency authorization for the use of various point-of care kits based on molecular and serological detection.

• Future research will aim at development of point of care devices and kits that can help in identification of the suspected patients from their homes so that visits to the hospitals could be minimized and more information could reach to health professionals and government agencies.

• The potential of techniques like loop-mediated isothermal amplification (LAMP), next generation sequencing, and CRISPER needs to be more extensively researched for bringing about the efficiency in diagnostic processes.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

Indian Council of Medical Research, Clifford Craig Foundation Launceston General Hospital, Tasmania, Australia.