Reverse Transcriptase Polymerase Chain Reaction for Covid-19 and Zika testing

PCR 

Polymerase Chain Reaction is an in vitro diagnostic technique. This is being used to amplify the DNA or RNA sequence of any source material. 

In the PCR process a target DNA sequence and DNA Polymerase enzyme is used in lab conditions, usually passing with following cycles in stages:

1. Converting dsDNA to single stranded DNA,  

2. formation of new dsDNA  with one old strand and one new strand,

3. using new dsDNA as an template to for synthesis in next cycles.

RT-PCR 

Reverse Transcriptase Polymerase Chain Reaction is also an in vitro diagnostic technique with a variation of PCR. In this process a mRNA sample with reverse transcriptase enzyme, a cDNA copy is obtained. Here onward a standard PCR process is followed in sequence to obtain the dsDNA sequence. 

RT-PCR and Covid-19 

Often RT-PCR is combined with the real time PCR (qRT-PCR) to quantify the transcript levels in cells/tissues.

Originally radioactive isotopes were used in this nuclear derived method; now replaced by the isotopic labelling with special markers like fluorescent dyes.

Conventional RT-PCR allows to see the result at the end of the process while in qRT-PCR one can see result immediately while the process is still on going. This technique has been used successfully in diagnosing Ebola and Zika virus and is now adapted for testing the Covid-19 virus.

Further reference for:

Virus, genome and Covid-19