Thread by @ScienceManCam

So how do we test for #COVID19? A thread

#COVID_19 is caused by a virus called #SARSCoV2 which is a non-living particle with genetic material that is surrounded by proteins and lipids that can cause disease. It's spread mainly by coughing and sneezing

1/n @AcademicChatter

We swab the nose because of how it spreads. The #coronavirus contains RNA which is it's genetic material that makes it a virus and let's it makes more of itself.

Once we have the swabs we extract this RNA with chemical reagents that leave us just the purified RNA

2/n #COVID19

We then use a technique called RT-PCR to detect for viral presence. RT-PCR uses fluorescent dyes that only become effective when it recognises a sequence which corresponds to the #Coronavirus

The PCR converts this RNA to DNA which we can detect with the fluorescent dye

3/n

As more copies of DNA are made by the machine the larger the fluorescent signal. After ~40 cycles we get a read out of the amount of signal, if it passed a threshold then it is a positive result (see @BioRender figure 5).

#SciComm @
4/n

These tests are very sensitive, and can be done in up to 8 hours on arrival of the sample. RT-PCR is currently one of the most accurate ways to detect viruses.

Unfortunately this method only tells us if you have an infection, and not if you have had it without knowing.

5/5