How Covid-19 testing is carried out in the laboratory

In rapid diagnostic testing, the antibody produced against the Covid-19 virus is taken advantage of. 

It is expected that any person that is infected with COVID-19 will have basically two types of antibody - IgM and IgG antibodies circulating in their blood.

The IgM type are the first type of antibody to be produced against the virus and it simply tells us that the infection is recent while the IgG are developed later in the process of the infection.

The rapid diagnostics test strips is a lateral flow immunoassay technique and uses the principle of paper chromatography. 

It is a method for detecting the presence of an unknown analyte in a sample and this case - covid-19 viral antibodies.

The test strips are impregnated with conjugated antigens (antigens to which an enzymes substrate is attached to and produces visible colour change when it reacts with a corresponding antibody).

So when someone's blood that contains the viral antibody or antigen is collected and a drop is placed on the region where the enzyme substrate are impregnated, a complex is formed and by capillary action. 

This complex formed then moves along the test strip until it finds its corresponding antibody, binds and consequently produces visible colour change.

Subsequently after the complete part of this article, I will give a well detailed laboratory procedure on how rapid diagnostic test for most samples are carried out in the laboratory.