Real-time reverse transcription polymerase chain reaction (rRT-PCR) is a molecular diagnostic testing technique of identifying the presence of specific genetic material in any pathogen, including a virus. Some viruses such as SARS-CoV-2, which causes COVID-19, only contain RNA. 

In order for scientist to accurately identify the early detection of COVID-19, they must convert RNA into to DNA through a process called reverse transcription. Unlike RNA, DNA can be amplified and copied through the method of polymerase chain reaction, which is a critical component for the detection of the virus.

The transcribed viral DNA is amplified hundreds of thousands of times so that there is a large enough quantity of target sections of viral DNA to accurately confirm the presence of the virus.