At the moment, with all the new tests that have appeared for COVID-19, there is still confusion about the difference, or purpose, of the various tests. Today we’re going to explain the difference between the antigen test and the antibody test.

What is an antigen test?

An antigen test is a diagnostic test where a mucous sample is taken with a cotton bud. After this procedure, the cotton bud is analysed to check if the patient is currently carrying the virus.

The results are obtained within 15 to 20 minutes. The tests detect a protein which is on the virus and whether the patient is in a highly infectious stage. It is a similar test to the PCR test, but has lower sensitivity. If what you want is to take a test with greater reliability and sensitivity, you should take a PCR test.

What is an antibody test?

The antibody test serves to check whether the body of the patient who has had the illness has generated antibodies against it, which we would consider to be immunity against COVID-19.

These tests are serological, that is to say, a blood test must be taken for analysis to check the existence of antibodies. In the case of rapid antibody tests, the results are available in 15-20 minutes.

What is the difference between an antigen and an antibody?

Many people confuse the two terms. Although the tests are very different and have a different purpose, many people think that the antigen test is the one detecting antibodies, and this is a dreadful mistake.

The main difference between antigen and antibody is that one detects the virus in the body during its most contagious stage and, on the other hand, the antibody test detects if the body has developed a defence against the virus.

The procedure for the two tests is completely different. While the antigen test takes the sample using a swab (slim cotton bud), the antibody test needs a blood sample.

When should I take each test?

Another difference between the antigen and antibody tests varies depending on the symptoms of the person and the person’s circumstances. A person who has been exposed to direct infection, who has signs of antibodies, or simply a person who wants to find out if they are infected, should take the antigen test.

However, a person who knows that they have had the virus, or has doubts about whether they have had it, or not, should take the antibody test to check that they have developed the defence.

Travel COVID-19 Test

If you need to take an antigen test to travel, or want to know if you have had the illness by taking an antibody test, you can do both at the Travel COVID-19 Test centres at Madrid, Málaga and Seville airports.