Serology Testing for COVID-19

In this article, we will discuss what serology testing is and whether it can be used to detect the presence of COVID-19, and what meaningful information it would provide. Recently, scientists from the Centers For Disease Control And Prevention have been conducting studies to determine the level of antibodies that provide protection against becoming infected with COVID-19 again. The serology testing can help to estimate how many people have been infected with SARS-CoV-2, this virus that causes COVID-19. But, what is the serology test, and can it be a PCR replacement?


Serology testing for COVID-19

What Is The Serology Test?


A serology test is a blood test that searches for antibodies within the serum of blood that could indicate your level of immunity. Different types of serologic tests can be used to diagnose various illnesses and diseases. While there are many different types of serology tests that can be performed if you are unwell or have been sick in the past, they all are designed to identify proteins called immunoglobulins. These proteins are specific to a particular past type of infection or form in response to vaccination. When your immune system reacts to the presence of virus proteins, also known as antigens, immunoglobulins (also called antibodies) are made to destroy these foreign invaders. Once your immune system has developed the right antibodies to help you recover from a certain disease or viral infection, your body will likely be able to fight it off much easier than a first encounter.


During a serology test, a healthcare professional will be able to test which types of antibodies and antigens are in your blood and understand whether you have been exposed to an infection or vaccinated against it or not.


How Is This Test Performed?


Unlike a PCR test which takes a sample from the nose and mouth to determine whether a virus is present, a serology test requires your serum, which is a fraction of your blood sample. Typically the blood sample is then processed by the laboratory for analysis or processed in the office in case of a rapid test. The covid antibody test at Safe Travels clinic can be processed in a doctor’s office, with results available in 15 minutes.


Can we use serology testing for COVID-19

What can the test results mean?


A negative rapid antibody test result means that antibodies for SARS-CoV-2 were not detected in your blood, and this could mean any of the below;


  • You have not been infected with COVID-19

  • You have not been vaccinated against COVID-19

  • You have been infected with COVID-19 or vaccinated against COVID-19, but your immune system hasn’t developed detectable antibodies yet (it takes several weeks to develop antibodies).

  • A false-negative result.


With positive results, there are several possibilities. In the case of a laboratory-processed antibody test, the test will indicate;

  • Whether you have been vaccinated and developed antibodies

  • Whether you have been infected by a virus in the past

  • Whether you have been both vaccinated and infected in the past

  • How long ago were you infected or vaccinated based on types of antibodies developed (IgM antibodies present will indicate past exposure measured in weeks, IgG antibodies will indicate past exposure measured in months)


In case of rapid antibody testing, the positive test will indicate:

  • Whether you have been vaccinated or exposed to the virus in the past without telling apart which one

  • How long ago were you infected or vaccinated based on types of antibodies developed (IgM antibodies present will indicate past exposure measured in weeks, IgG antibodies will indicate past exposure measured in months)



In addition, only some specific laboratory tests will quantify the amount of antibodies to tell how strong the antibody response is. In the case of a rapid antibody test, this is not the case; the result will be either positive or negative. A serology test could also provide a false-positive result in rare cases, which means the patient has recently recovered from a common cold.


In rare cases, a serology test could also provide a false positive result - which means the patient has recently recovered from a common cold.


Most importantly, it is crucial to keep in mind that a positive antibody test doesn’t necessarily mean that you are now immune from COVID-19. It also does not stand as equivalent to vaccination and will not replace vaccination. It cannot be used as of today as proof of vaccination. This is because, according to the current state of knowledge, immunity from exposure to a natural virus in the past does not cause immunity as robust as immunity from the vaccine. So it should not suggest that you are protected from future infection of COVID-19.



serology testing for COVID-19 fit to fly

Can It Be Used For International Travel?


Unfortunately, with few exceptions, such as requirements of travel to China, a serology test is not generally used to diagnose COVID-19 for travelling abroad. These tests may even produce a negative result even if a patient is actively suffering from the virus. Due to the possibility of false-positive and false-negative results, they are not currently used as a PCR or rapid antigen replacement. However, evidence is building regarding the importance of neutralizing antibodies and how this can reflect immunity.


Italy’s ISS national health institute published research on 162 patients with symptomatic coronavirus neutralizing antibody tiers, which progressively drop after 5 to 8 weeks, yet are detectable up to 8 months later. And in Sydney, Australia, researchers are studying the relationship between neutralizing antibody levels and protection from disease. The scientists found that neutralizing antibody levels were highly predictive of immune protection. So, perhaps in the future, a serology test will be used worldwide for international travel, but at the moment, the results of this type of test are just not reliable enough.


While antibody tests are not generally accepted as an alternative to a PCR or rapid antigen test, you can still book an antibody test at our clinic in Windsor, Ontario. It is mostly used at our clinic for peace of mind and to confirm the suspicion of past virus exposure. Currently, very few countries require laboratory-based antibody testing, and if this is needed, we will conduct this test for our patients. It’s best to check the entry requirements of the country you’re planning to visit before deciding which test to book.


Fit To Fly COVID-19 Tests


If you do have an overseas trip coming up, you’ll probably need to book a PCR test in Windsor, Ontario. At Safe Travels Clinic, we offer highly accurate PCR tests and rapid antigen COVID-19 tests for Canadians travelling abroad. While you will need to be vaccinated to fly from Canada to another country from the end of October 2021, most countries still require tourists and foreign travellers to provide a negative PCR test or rapid antigen test before entering the country. Failing to provide these tests could mean being told at the boarding gate that you cannot board the plane! So rather than take this risk, it’s always best to book a COVID-19 Fit to Fly test a couple of days before your trip.


How To Book A Fit To Fly COVID-19 Test In Windsor, Ontario?


To book a COVID-19 test in Windsor, Ontario, simply head to our website and select the test you would like to book. Once you have paid for your test and have confirmation of your booking, visit our clinic for the test to be performed. When your results are ready, we will send you an email detailing your COVID-19 test results. If you have any questions about travelling internationally as a Canadian citizen and booking a PCR test, feel free to contact our team today! We would be more than happy to answer your questions and queries and help you to start exploring the world once again.


References:

1:https://www.cdc.gov/coronavirus/2019-ncov/lab/serology-testing.html

2:https://www.healthline.com/health/serology

3:https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/antibody-serology-testing-covid-19-information-patients-and-consumers

4:https://www.abingdonhealth.com/antibody-testing-unlock-hard-hit-sectors-aviation-travel/