A few years ago the ability to measure sequence of proteins in an RNA strand was limited and slow. But now millions of RT-PCR tests are being done every day and overnight to detect the marker strands of antigens to the Covid-19 virus.
Many people are confused by statements such as PCR is not a test. Which is correct. The test is reverse transciptase where a mirror image of the sequence of proteins created by the bodies immune response to infective virus (antigen) is compared to the sample following a complex extraction process. The PCR is an amplification process that converts the needle in a haystack of RNA to many needles in less haystack. At the same time a control is also amplified and so the comparison is with the amount in the amplified control.
There is a video explaining the test here http://<iframe width=”1280″ height=”720″ src=”https://www.youtube.com/embed/ThG_02miq-4″ title=”YouTube video player” frameborder=”0″ allow=”accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture” allowfullscreen></iframe>
The video shows a lot of hand processes but increasingly the steps are automated and the quality control logged to central databases so anomalies can be checked.