FAQs – COVID-19 IgG Antibody Testing

What are antibodies?

In humans there are 5 types of Immunoglobulins: IgG, IgM, IgA, IgE and IgD. IgG antibodies, which make up one of the 5 types of immunoglobulins, is the most abundant immunoglobulin in the human body, accounting for approximately 75% of immunoglobulins. IgG immunoglobulins are largely responsible for the development of long-term immunity, after viral infection or post-vaccination, against an infectious disease. IgM antibodies are the second most abundant and make up 10% of human immunoglobulins. IgM immunoglobulins aid in determining immunity to viral infections, as it is first to develop during the early phase of infection.

 

What is the COVID-19 IgG antibody test?

Approved by Health Canada on May 14, 2020, this blood test is used to identify if there is a presence of IgG antibodies that are specific to COVID-19 infection. Unlike the swab test that’s currently being provided by the City of Toronto, antibody testing won’t tell you if you have an active infection. Instead, your results may help identify if you have been previously exposed to COVID-19.

 

When will the COVID-19 IgG antibody test be available at Medcan?

It should be available in August. We recommend getting in touch with us at that time to confirm the availability of any testing options.

 

What type of lab equipment is being used to process the COVID-19 IgG antibody tests?

Medcan is using the Abbott Architect 8200 analyzer.

 

How accurate is the Abbott COVID-19 IgG antibody test?

The Abbott antibody test has a percent positive agreement of 100% and a percent negative agreement of 99.63% fourteen days after the onset of symptoms. This means that it can detect the IgG antibody that is developed fourteen days after the onset of COVID-19 symptoms with 100% accuracy and, if the antibody has not been developed, with 99.63% accuracy.

 

Is the cost of the test covered through medical insurance?

Currently, this test is not covered by OHIP, meaning you will be required to pay out of pocket. For more information on insurance coverage and the COVID-19 IgG antibody test, we suggest you contact your medical insurance provider.

 

What do the antibody test results mean?

If your test result is positive, this means that IgG antibodies were detected in the sample you provided, suggesting that you have been exposed to COVID-19.* There is not enough evidence to determine if IgG antibodies provide protective immunity against COVID-19.

*If you were previously diagnosed with or exposed to other types of coronaviruses, there is a possibility of a false positive test result, which would indicate that you have IgG antibodies when you actually don’t. There’s also a possibility of a false positive if it’s unlikely that you had COVID-19 based on your exposure history or symptoms.

If your test result is negative, this means IgG antibodies were not detected in the sample you provided, suggesting that you were not exposed to COVID-19 or have not yet developed IgG antibodies.* If you believe you have been exposed to someone with COVID-19 or you develop symptoms of COVID-19, you should self-isolate and follow-up testing with a molecular test (PCR) should be considered to check for active infection.

*If you were recently diagnosed with COVID-19, were exposed to someone with COVID-19, or previously had symptoms of COVID-19, there is a possibility of a false negative test result, which would indicate that you do not have IgG antibodies when you actually do. If you test too soon, your body may not have produced enough IgG antibodies to be detected by the test. If that’s the case, retesting may be required.

 

I tested positive. Now what?

If your test result comes back positive, you may want to arrange for a follow-up visit with your healthcare provider to determine if further testing is required. This will depend on your physical presentation (i.e. if you have current or recent symptoms of COVID-19 or if you have been exposed to COVID-19).

 

My test result is positive. Do I have COVID-19?

Not necessarily. The COVID-19 IgG antibody test does not determine active infection. It only confirms recent or previous exposure to the virus. If you suspect that you have COVID-19, you should consult with your healthcare provider to arrange COVID-19 viral testing.

 

My test result is positive. Do I need to isolate?

It is important to maintain social distancing, appropriate hand hygiene and use of face masks whenever possible. If your IgG test result is positive, it could indicate a previous exposure to COVID-19 without determining whether you have an active infection. If there’s a chance you have an active infection based on exposure or symptoms, you should isolate and seek confirmatory testing via nasopharyngeal swab.

 

My test result is positive. Can I be re-infected with COVID-19?

Testing positive for IgG antibodies to COVID-19 does not mean re-infection is not possible. Currently, it remains unclear to experts whether people who are positive for IgG antibodies are immune or susceptible to re-infection or future infection since the relationship between antibodies and immunity to infection with COVID-19 is unconfirmed.

 

My test result is negative. Am I at greater risk for COVID-19?

Your negative antibody test indicated that no antibodies were currently present in the sample you provided, suggesting that you have not been previously exposed to COVID-19 infection.

However, if you were recently infected with COVID-19, there is a chance that antibodies may not have developed yet. Further discussion with your healthcare provider may be required.

 

Does my test result affect my ability to return to work?

Your COVID-19 IgG antibody test result suggests presence or absence of prior exposure to COVID-19. It does not provide information on ability to return to work.

My test result is negative, but I was previously confirmed positive for COVID-19 via another testing method. What does this mean?

If you are recently or currently infected and/or asymptomatic, IgG antibodies to COVID-19 may not have developed yet, explaining your negative result. Additionally, some individuals may take longer to develop IgG antibodies even though they have been exposed to the infection. A further discussion with your healthcare provider is necessary, as an additional test or assessments may be required.

 

How long does it take to get my results?

You will be informed of your test results by a Medcan staff member and a COVID-19 IgG antibody Client Report will be provided to you within six days of your test through myMedcan, our secure online portal. Should you have any questions, a Medcan health professional will be available to review your results with you.

 

How many times can I take this test?

Since research is still being collected at this time, no clear indication related to frequency of testing has been approved.

 

Resources

Abbott. (2020). Abbott Launches COVID-19 Antibody Test. Retrieved from: https://www.abbott.com/corpnewsroom/product-and-innovation/abbott-launches-covid-19-antibody-test.html

Abbott. (2020). How does COVID-19 antibody testing work? Retrieved from:
https://www.abbott.com/corpnewsroom/product-and-innovation/how-does-COVID-19-antibody-testing-work.html

Abbott. (2020). Top COVID-19 Antibody test questions. Retrieved from:
https://www.abbott.com/antibody-testing/top-COVID-19-antibody-test-questions.html

Centers for Disease Control and Prevention. (2020). Coronavirus disease 2019 (COVID-19): Test for past infection (Antibody test). Retrieved from: https://www.cdc.gov/coronavirus/2019-ncov/testing/serology-overview.html

Government of Canada. (2020). Serological tests for use against COVID-19. Retrieved from: https://www.canada.ca/en/health-canada/services/drugs-health-products/medical-devices/covid-19/serological-testing.html

Jacofsky, D., Jacofsky, E. M. & Jacofsky, M. (2020). Understanding antibody testing for COVID-19. The Journal of Arthroplasty. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7184973/

LifeLabs. (2020). Current state of diagnostic and serological testing for COVID-19 disease. Retrieved from: https://lifelabs.azureedge.net/lifelabs-wp-cdn/2020/05/Molecular-and-
Serological-Testing-for-COVID-19.pdf

You may also be interested in: