Fluctuating RT-PCR CT values: A case series

Real-Time Reverse Transcriptase Polymerase Chain Reaction (r RT-PCR) has been the main diagnostic tool for SARS-CoV-2 infection since the early stages of the COVID-19 pandemic and a positive test enables the clinicians and public health professionals to quickly isolate the patient and prevent spread of the disease. The presence of viral RNA confirms SARS CoV-2 and the Cycle Threshold (Ct) values may give a rough estimate of viral load. Theoretically, the Ct value is inversely proportional to the amount of genetic material (RNA) in the starting sample and lower Ct values is generally associated with high viral load. Some experts assume that high viral load is directly correlated with increased infectiousness and severity of disease and suggest using Ct value or calculating viral load in decision-making. As per the policy, dated 14th June 2020, National Health Strategic Command Group in Qatar recommends using RT-PCR Ct value as a key determinant for decision on admission, discharge and isolation. The objective of this case series is to show that Ct values vary as the course of infection progresses, hence cannot be used as a reliable marker to take clinical decisions or even public he