COVID-19 antibody testing: what is it & how does it work

Advice  -  October 21st 2020

COVID-19 antibody testing: what is it & how does it work

What is COVID-19 antibody testing?

Recently, considerable attention has been put on the different tests for COVID-19; especially the extensively discussed antibody test, which is now available to the wider public. But what is antibody testing, and why does it make sense to provide your employees with regular antibody tests? In this article, we’ll give you the rundown on antibodies and antibody testing.

What are antibodies?

Whenever our bodies are infected with a disease by bacteria or viruses, or if an allergy is triggered by allergens, our immune system will create antibodies. Normally, antibodies – also known as immunoglobulins – are produced within one to three weeks after the disease has been contracted. Every disease will trigger the production of different antibodies; this is important to identify the type of disease a person is suffering from.

There are different types of immunoglobulins, and some of them might occur in other bodily fluids than the blood (like tears and saliva), but for the detection of the novel Coronavirus, two types of immunoglobulins play a vital role: the antibodies IgM and IgG.

Antibodies are an immune response to COVID-19 and their presence can inform an individual that they have previously been infected. IgM antibodies tend to imply an acute infection while IgG antibodies are indicative of possible long-term immunity to future infection. Antibody tests can also be incredibly useful at conveying the prevalence of the virus within the community and would be useful to show how many people are still vulnerable to infection reinforcing the necessity of practicing strict social distancing measures.

IgM is the first antibody that the immune system produces after a disease has been contracted. IgG is the most common antibody that can be measured in the blood after bacterial or viral infections. It usually takes the body a bit longer to produce IgG but in many people they are produced at similar times.


Coronavirus symptoms graph

As seen in the graph above, it can take a couple of weeks for antibodies to be produced and antibody tests are therefore much more effective at helping you to monitor which employees are sustaining their immunity to the virus. Anyone who is suspected of having a current COVID-19 infection must seek a PCR test.

The presence of IgG and absence of IgM and a negative PCR test excludes an active infection and means the player would be less likely to contract COVID-19 or pass it on to others through breathing – however they can still transmit the virus by hand. Should an employee display presence of IgM only it is heavily advised they then seek a PCR test to confirm whether the infection is presently active as these antibodies do tend to be produced during the acute stage but this can vary and therefore PCR needs to be used to corroborate any diagnosis.

The testing protocol suggested is MEDsan rapid testing twice a month to monitor immunity and PCR 2 or 3 days before each match to rule out current infection unless solely IgG positive

It is not yet known how long the antibodies to COVID-19 remain in our system, and if everyone who has suffered from the disease will develop the antibodies.

What is an antibody test?

An antibody test, also known as a serology test, determines whether someone has already had a disease. Usually, it is carried out by examination of a blood sample; a drop can often be enough.

The blood sample will be tested for the presence of antibodies (immunoglobulins). In the case of most COVID-19 antibody tests, the blood will be tested for IgG (the antibodies that develop one to three weeks after infection). Some antibody tests, such as MEDsan’s rapid COVID-19 antibody test, will also test for IgM. A positive presence of IgM can indicate a recent infection. If you test positive for IgM antibodies only it is recommended you seek a PCR test to confirm if the infection is current.

What can a COVID-19 antibody test tell you?

Most COVID-19 antibody tests can tell you whether you have previously been infected with COVID-19. This is especially helpful if you have shown symptoms, but did not have a swab test to confirm that it is COVID-19 that you are suffering from or if you think you might have contracted the disease but haven’t displayed any symptoms. For research purposes, it is essential to understand how and where the virus has spread.

Does a positive antibody test mean you are immune against COVID-19?

There is still no evidence to suggest that someone who has had COVID-19 once can’t contract it a second time. This means that even if you have had a positive result on the antibody test, you could get the virus again and infect other people with it. Regardless of your result, you will still need to follow all the necessary safety measures like social distancing and face coverings.

Where can I get an antibody test?

In the UK, the government is currently providing free antibody tests to workers in certain professions, but this does not mean that the only alternative is a paid-for test at a private clinic. It is possible to order rapid COVID-19 antibody tests for your employees through our website. To ensure the safety of your employees and the flawless functioning of your business despite the ongoing global pandemic, we recommend each employee regularly carries out a test at home, so they – in the worst case – can spot the disease early, self-isolate, and contain the virus.