Correlation of COVID-19 RT-PCR CT values and symptoms, duration and medication of patients.

Abstract

Coronaviruses (CoVs) belong to the subfamily Orthocoronavirinae in the family Coronaviridae, Order Nidovirales. There are 4 genera inside the subfamily Orthocoronavirinae, like Alphacoronavirus (α-CoV), Betacoronavirus (β-CoV), Gammacoronavirus (γ-CoV) and Deltacoronavirus (δ-CoV). The CoV genome is an enveloped, positive-sense, single-stranded RNA with a dimension various between 26 kb and 32 kb, the biggest genome of recognised RNA viruses.

Real Time Reverse Transcription Polymerase Chain Reaction (Real Time RT-PCR) is the gold widespread test for detection of SARS-CoV-2. This test allows early detection of viral genome in medical samples. A positive test permits the clinicians and public health experts to rapidly isolate the affected person and stop progression of the disease. The cycle threshold or Ct value of a RT-PCR response is the number of cycles at which fluorescence of the PCR product is detectable over and above the background signal. Theoretically, the Ct value is inversely proportional to the quantity of genetic material (RNA) in the beginning sample and decrease Ct values usually correlate with excessive viral load. It is being assumed with the aid of some researchers / clinicians that excessive viral load immediately correlates with elevated infectiousness and severity of disease. ICMR has mentioned the problem of correlating COVID-19 disease severity with Ct values and consequently figuring out on affected person management protocol, with a panel of esteemed laboratory experts. Real-time RT-PCR protocols for detecting SARS-CoV-2 in different countries. Three fluorescent indicators from FAM, ROX, and CY5 channels detected the viral replica DNA (cDNA). We selected the nucleocapsid protein gene N and the RNA-dependent RNA polymerase gene (RdRP) [also stated as Open Reading Frame 1ab (ORF1ab)]. Internal control helped to check for biases of the complete procedure. We used a positive control such as plasmids containing the whole SARS-CoV- two N gene in our study. In this study the reports that has been taken for the  survey has selected these markers as control.