A guide to laboratory diagnosis of Corona Virus Disease-19 for the gastroenterologists

Abstract

The outbreak of Corona Virus Disease-19 (COVID-19), caused by Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2), a global pandemic, is having a significant impact on healthcare, especially the clinical microbiology laboratories all around the world. There are many reports which suggest that the disease can present with gastrointestinal symptoms such as nausea, vomiting, diarrhea, and loss of appetite, which the gastroenterologists may have to deal with. Hence, knowledge about the diagnosis of COVID-19 is important to gastroenterologists as well. The current review therefore covers the challenges faced while choosing appropriate sample collection, transport, and tests for SARS-CoV-2 infection. The right sample at the right time from the right anatomical site with the proper precautions is crucial in prompt and accurate diagnosis of COVID-19. The tests can be divided into direct, indirect, and complementary tests. In the direct test, real-time polymerase chain reaction (RT-PCR) assays are the molecular tests of choice for the diagnosis of COVID-19. Other direct tests include GeneXpert and TrueNAT. In indirect testing, antigen-antibody-based techniques are recommended for surveillance for the disease, which may help to formulate the control measures. Finally, the additional tests help in assessing the disease severity and evaluating the prognosis. All the above tests are important not only for diagnosis but also for management strategy and prognosis.

COVID-19: Rapid antigen detection for SARS-CoV-2 by lateral flow assay: A national systematic evaluation of sensitivity and specificity for mass-testing

“…The current diagnostic test involves reverse-transcription polymerase chain reaction (RT-PCR) testing of nose/throat swabs in specialised laboratories. Such capacity in the UK is currently estimated at ~500,000 tests/day [4] , [5] , [6] , [7] . and this is used with contact tracing procedures and mobile applications to identify close symptomatic contacts of infected symptomatic individuals [8] , [9] , [10] .…”

COVID-19: Rapid Antigen detection for SARS-CoV-2 by lateral flow assay: a national systematic evaluation for mass-testing

“…tests/day [4][5][6][7] and this is used with contact tracing procedures and mobile applications to identify close symptomatic contacts of infected symptomatic individuals. [8][9][10] However, there are significant challenges in creating testing capacity to identify those with asymptomatic infections or to test contacts of individuals with COVID-19.…”

COVID-19 and Dentistry in 72 Questions: An Overview of the Literature

“…The highest viral loads are usually detected in the airways 5 to 6 days after the onset of symptoms. The swabs are then placed in a viral transport medium and can be kept for up to 72h at 2–8 °C, but should be stored below −70 °C for longer time [ 162 ] The rRT-PCR (real-time Reverse Transcription Polymerase Chain Reaction) assay, which relies on the recognition and amplification of viral RNA, is the “gold standard” for diagnosing COVID-19 [ 163 , 164 ]. The interpretation of rRT-PCR results is based on the number of amplifications that are necessary to obtain a detectable fluorescent signal, named cycle threshold (Ct).…”