Here's the process involved in the testing of a person for Coronavirus

The most commonly used COVID-19 test uses polymerase chain reaction (PCR), a technique invented in 1980s central to PCR is its ability to 'amplify' DNA - multiply genetic material into large enough quantities to analyze. In the case of coronavirus, the virus' RNA initially needs to be converted to DNA using an enzyme called reverse transcriptase before putting samples into the PCR machine. Samples collected in the throat and nasal swabs are mixed with reagents which are particles that bind to the virus genetic material to ensure no other type of DNA in the sample is amplified.  The sample is placed in a PCR machine that uses cycles of heating and cooling to help the reagents amplify the target DNA into millions of copies. A fluorescent dye is added - the dye glows if the result is positive.

Here is the process involved in a COVID-19 test

1. A swab is taken from the patient

2. The sample is then sent to a lab

3. The virus' genetic material is turned into DNA through reverse transcription 

4. Reagents, known as probes & primers, are added & used to target certain parts of DNA

5. If the DNA target is present, it will be multiplied many times; will create a flash of light

6. The diagnostic machine records the level of light & compares it with +ve & -ve samples

7. If there is a lot of light, the sample is positive for Coronavirus