ABSTRACT
<strong>BACKGROUND</strong> The novel coronavirus disease (COVID-19) has exposed the chinks in the armour of healthcare systems and has single-handedly literally brought the world to a standstill. Diagnostic testing for COVID-19 is critical for understanding epidemiology, contract-tracing, case management, and to control the transmission of the SARS-CoV-2. RT-PCR test, the gold standard test, involves fairly complex steps and take nearly 24–48 h for generating the results. GeneXpert is a rapid nucleic-acid-detection-based test approved by ICMR (Indian Council of Medical Research), which can shorten the turnaround time significantly.AIMThe aim of the study was to compare the performance of GeneXpert against the gold standard RT-PCR for SARS-COV-2. <strong>MATERIALS AND METHODS</strong> This retrospective study was conducted at a tertiary care centre from 25th March 2020 to 8th December 2020. The Nasopharyngeal/Oropharyngeal swabs that were sent to the Covid laboratory for testing of SARS COV-2 by GeneXpert (CBNAAT) were included for the study. The samples that gave a positive result were simultaneously tested for rRT-PCR. According to the manufacturer instructions, the cut-off value for GeneXpert is 45 whereas according to ICMR, cut-off value for RT-PCR to be taken is 35.RESULTSOut of 220 samples positive by GeneXpert , 102 (46%) showed negative results by RT-PCR. Among these 102 samples, 89% (91/102) samples were found to be positive by GeneXpert with Ct value >35 whereas 90% (96/107) positive GeneXpert samples had Ct value <35 which were also positive by RT-PCR. <strong>CONCLUSION</strong> The formulation of certain cut-off Ct values for the uniform results by both GeneXpert and RT-PCR should be implemented.
ABSTRACT
The novel Coronavirus COVID-19 is wrecking a havoc across the globe and has been declared as a pandemic by WHO. Apart from transmission and shedding of the virus through respiratory secretions in the form of droplets (mainly), several studies have shown the presence of the virus in various samples such as stool, urine and occasionally in blood, semen, tears and breastmilk. Whereas government authority guidelines consider a person as cured from COVID-19 when along with clinical improvement no more virus can be detected primarily on respiratory samples along with clinical improvement; the persistence of the virus in these body fluids even after clinical recovery and negative RT-PCR test results on respiratory samples, has raised many questions about the elusive nature of this novel virus along with the possibility of other routes of transmission of this virus in the community. Although studies performed till now across the globe on persistence of SARSCOV-2 in various body fluids are sparse, in this review we would like to present and analyse the results of those studies performed globally on the aforesaid topic to get a better insight of this side of the COVID-19 story.
Subject(s)
COVID-19/genetics , Genome, Viral , Reinfection , SARS-CoV-2/genetics , COVID-19/diagnosis , Humans , India , Male , Middle Aged , Polymorphism, Single Nucleotide , RNA, Viral/genetics , Time FactorsABSTRACT
After the havoc created by Spanish flu a century ago, the world is witnessing exactly a similar pandemic situation since the beginning of the year 2020. The unexplained respiratory illness with high morbidity & mortality which started in Wuhan, China and spread across the world was finally termed as COVID-19 disease caused by SARS-CoV-2 and later announced as pandemic by WHO. This novel virus SARS-CoV-2 is a new variant of SARS corona virus with high infectivity and mysterious pathophysiology. The major step towards containment of this pandemic is to scale up the testing for SARS-CoV-2 and thereby isolating and managing the patients at the earliest. Molecular amplification based methods such a Real time Polymerase chain reaction (RT-PCR), CBNAAT and TrueNAT are the most commonly used techniques for detection of SARS-CoV2. To utilize these diagnostic facilities optimally in the management of the suspected COVID 19 patients, it is of utmost importance for the healthcare providers to understand the intricacies related to these technologies. Thus, the technical details along with the pros & cons of these three amplification-based technologies for proper understanding of these diagnostic modalities for SARS COV-2 diagnosis are discussed herewith.