Worldwide, large quantities of COVID-19 tests have been purchased, because the corona virus was able to spread at a rapid pace. These COVID-19 tests were purchased in order to be able to detect the virus quickly and to isolate infected people in time. With this, the national governments and health institutions worldwide wanted to tackle the virus and try to prevent it. In the Netherlands, 3 COVID-19 tests are used. We are talking about the PCR test, the IgG / IgM Antibody rapid test and the Antigen (Ag) test. In this post, we would like to discuss the difference between these 3 COVID-19 tests and when which test should be used. This way you have the three COVID-19 tests in a row and that immediately provides a clear overview.
After the first contamination, much use was made of the PCR test. This test is used by the GGD to detect pieces of SARS-CoV-2 at the molecular level. This happens in the nose and / or throat mucus or other areas in the airways. This test can indicate whether specific virus genes are present on the sample taken. If that is the case, we speak of a corona infection. The abbreviation of the PCR test stands for Polymerase Chain Reaction. This is a PCR technique used in the analysis of the sample taken after testing. This analysis means that genetic material of the virus is propagated in the laboratory. This can then be accurately detected.
The advantages of this test is that the PCR test is very sensitive and accurate. This makes it possible to test very accurately for COVID-19, because the PCR test can distinguish this virus from similar viruses. Another advantage is that the PCR test can detect an acute contamination. If the PCR test shows a positive result, it is therefore certain that an infection has actually taken place and that the person is actually carrying the virus.
There are some limitations to the PCR test. That is the fact that it is a lengthy process. The results will have to be waited 24 to 48 hours. This is because the collected samples have to be sent to a specialized laboratory for analysis and to perform the PCR technique.
In addition to the PCR test, the rapid test IgG / IgM Antibody is also widely used. These are reliable rapid tests that can detect antibodies against SARS-CoV-2 in the blood. The IgG / IgM Antibody Rapid Test is used for people who want to know if they have been infected with the COVID-19 virus in the past. This is because antibodies are produced by the immune system to fight infections. If this test shows a positive result, the person in question has been infected with the COVID-19 virus.
This test has the advantage that it can be shown whether contamination has occurred in the past. Even people who have not had any complaints may still have been infected with the virus. In addition, the IgG / IgM antibody rapid test is a very reliable test. This test will show the results within 15 minutes.
There are some limitations to this test. For example, testing can only be done for contamination in the past. This test is not very sensitive to active infections. Another limitation is that it is not yet known whether people who have been infected with COVID-19 are really protected against the virus by the body's own antibodies. This is still under investigation.
Antigen (Ag) test
A few months after the first COVID-19 contamination, the Antigen (Ag) test was also developed. This test serves as an alternative or addition to the other two tests. The Antigen (Ag) test can detect antigens present. These are pieces of protein that are part of the SARS-CoV-2 virus in collected nasal mucus. It is a test that can quickly show the result. This quick test can show after 15 minutes whether the person being tested is infected with COVID-19. Another advantage of this test is that it can be shown whether the virus is present in the person, even before the body has produced antibodies. The proteins that the Antigen (Ag) test investigates are released to our body cells fairly quickly after a COVID-19 contamination has taken place. However, antibodies are only produced by our immune system days after contact with the virus.
The Antigen (Ag) test also provides an indication of both contamination and infectivity. If there is an active infection, the person can infect another and, therefore, an infectious person must immediately be in isolation. In addition, this test can also test asymptomatically. The Antigen rapid tests, in contrast to the PCR tests, are used preventively in humans in some countries. This test can be used in people who have emerged from the source and contact research, but no symptoms yet