Towards effective diagnostic assays for COVID-19: a review

Abstract

<jats:p>Countries globally are affected by the COVID-19 pandemic, with nearly two million cases and 120 000 deaths occurring within 4 months of the discovery of the severe acute respiratory syndrome coronavirus-2 in December 2019 in China. Accurate diagnoses of cases is key in managing the pandemic by identification, isolation and treatment of patients and defining the epidemiology of the virus. By mid-January 2020, a scientist from China published the full genome of the virus, which facilitated the development of accurate molecular diagnostic assays. By the end of January 2020, the WHO, in collaboration with laboratories in Asia, Europe and the USA, published several real-time reverse transcriptase PCR (rtRT-PCR) protocols that allowed identification of cases and development of commercial assays. Clinical investigations facilitated development of accurate case definition and guidance for laboratories on the optimum specimens and procedures for diagnoses. Currently, laboratory-based rtRT-PCR is the recommended test for diagnoses of acute cases to ensure patients can be identified and isolated and to facilitate the public health response. However, due to delays in diagnoses, severe shortage of tests and laboratory capacity, point-of-care molecular or antigen tests are becoming more attractive. Although serological tests are not suitable for diagnoses of acute cases, they are important to define epidemiological questions, including attack rate in the population, and to identify immune individuals. This review aimed to summarise the current available information for diagnoses of cases and to aid laboratories and healthcare workers to select the best assays and procedures.</jats:p>

Head-to-head comparison of four antigen-based rapid detection tests for the diagnosis of SARS-CoV-2 in respiratory samples

“…Sensitivity is the most important performance parameter of SARS-CoV-2 antigen detection (12). However, it is also considered the main limiting factor due to experiences with influenza and RSV lateral flow detection kits (6, 25). Newer biosensor-based methods to detect SARS-CoV-2 antigen have shown promising results and could offer a highly sensitive alternative for rapid diagnosis in the future (26, 27).…”

Assessment of the direct quantitation of SARS-CoV-2 by droplet digital PCR

“…SAR-CoV-2 is an enveloped, non-segmented, positive sense RNA virus that is included in the sub-family Coronavirinae , subgenus Sarbecovirus 1 . As of today, reverse transcriptase real-time PCR (RT-PCR) technology is used as molecular diagnosis for the SARS-CoV-2 and various protocols have been developed and used in the clinical laboratories worldwide 2 , 3 . The majority of protocols includes the RNA extraction and purification process before RT-PCR as a necessary step for the measurement of viral RNA load, as it isolates the genomic RNA from the viral capsid and removes PCR-inhibitors from the original material 4 .…”

REMBRANDT: A high-throughput barcoded sequencing approach for COVID-19 screening

“…Several diagnostic approaches that can provide fast and cheap tests have been developed. One of the leading approaches uses blood tests to identify IgG and IgM antibodies against SARS-CoV-2 proteins (15). These tests show great promise.…”