Whether you have been recently vaccinated or caught Covid-19 naturally, this IgG test will confirm whether your immune system has developed neutralising IgG antibodies and give you a quantitative measure of your body’s response (between levels of 0 – 80,000 AU/ml).

It will help you to know how your immune system has responded to vaccination or an infection to confirm whether the illness you had was Covid-19 or something else.

IgG levels often reduce quite quickly in the months after an infection and this test will enable you to monitor your IgG levels over time to see if your levels are dropping to below the levels that may be assumed to give immunity.

How is this test different from the older antibody tests and what will it tell me?

The older IgG and IgM antibody tests checked if you had antibodies in your system from being infected with Covid-19 in the past. 

With this new quantitative test – produced by the world’s leading laboratory diagnostics provider – you will know if you have had Covid-19; and if your vaccination has worked. You will also get an accurate measure of by how much your immune system has responded. This is a great improvement and gives you much more useful information than was previously available to us.

Your sample will be analysed for the actual level of IgG antibodies in your body. If you receive a positive result, this is because the test detected an AU/ml level of above 50 units, which can be taken to confirm that you have been either been exposed to coronavirus or that your body has produced an immune response to your vaccination.

This latest IgG test also measures a different viral protein than the previous one (from May 2020). The old IgG test would not measure whether your body has responded to the different vaccines whereas this new test does. This quantitative IgG test measures your levels of IgG antibodies against the spike receptor-binding domain (RBD) of SARS-CoV-2 whereas the previous test measured IgG against nucleoprotein. The spike protein is the main protein that is associated with the body mounting an immune response. It is also the protein which all the immunisations are mimicking to get the body’s immune system to fight off the virus so this test will tell you how well your body has responded to the vaccine.

Please note, it is not yet clear how your immune response relates to whether you are immune or not. Please see this whitepaper for more details. Research into this is ongoing so do not presume you are immune – even with a positive result. This virus has not been around for long enough for the scientists to be sure at what levels of IgG antibodies makes you immune, even at high levels. Although, a recent study has shown not developing antibodies from a vaccine against the virus has been linked to increased hospitalisation and mortality and this may be 1 in 100 of people.

There is evidence for IgG antibody levels as an indicator of protection against COVID-19 vaccines but this is still currently undergoing research. This recent paper asks whether an antibody response can protect against Covid-19 and the team shows “that neutralization level is highly predictive of immune protection, and provides an evidence-based model of SARS-CoV-2 immune protection that will assist in developing vaccine strategies to control the future trajectory of the pandemic.”

A similar result was seen in an earlier paper where higher ratios of IgG spike protein antibodies were seen in outpatients who had mild illness versus severely ill patients again suggesting higher IgG against the spike protein protects against severe illness.

When should I take this test?

This test is best taken at least seven days after your initial coronavirus infection or vaccination. Your levels are likely are to continue to rise up to 15 days when it is 99.4% sensitive in confirming your exposure to the spike protein of the virus.

If I test positive, how long will the IgG levels last?

It is not known how long antibodies will last, as research into this is ongoing. There is evidence that people’s immune response to infection drops off significantly over 6-9 months. It is as yet unknown how long your IgG levels remain high after vaccination. This test will be a very valuable tool in helping scientists to monitor this.

Will this test tell me if I currently have coronavirus or are infectious?

No, this test will only determine whether your body produced IgG antibodies in your blood which occur over 7 (and for best results at least 15) days after a Covid-19 infection or a vaccination.

If you would like to check whether you currently have coronavirus present, then please take our Coronavirus PCR Swab Test.

If you would like to check whether you are currently infectious with coronavirus, then please take our Coronavirus Rapid 15 Minute Antigen Test.