The test looks for antibodies against SARS-CoV-2 in your blood. Check where you can get tested in Warsaw. How to interpret the results, and what antibody levels make us immune to coronavirus?
- What is antibody testing?
- When should you perform an antibody test?
- Where can you do an antibody test in Warsaw?
- Recommendations of the Damian Medical Centre regarding different types of serological tests
- Interpretation of serological tests
What is antibody testing?
Antibodies are types of protein that can recognize antigens. They are produced by our immune system and protect your body from viruses and bacteria. Their presence in the blood while testing for antibodies provides important information about the infection.
Antibodies come in 5 classes: IgG, IgM, IgA, IgE, and IgD. IgG antibodies are the most persistent and remain in the body for a long time after the infection has healed. In turn, IgM antibodies are produced the fastest.
Antibody tests check if you had coronavirus before with no symptoms (IgG class) or if you are still infected (IgM or IgA class). Positive antibody tests result should be confirmed by RT-PCR.
When should you perform an antibody test?
Unlike RT-PCR tests, which are very important in the early phase, antibody testing is performed at a later stage of the infection.
This type of diagnosis is significant for people who have had COVID-19 with mild or no symptoms. The IgM antibodies in the blood may indicate an active infection, but they can be detected 7 to 10 days after the first coronavirus symptoms. The IgG antibodies in the blood indicate a past contact with the virus. Performing the test in both classes simplifies the interpretation of the result.
The IgM class of antibodies (the so-called acute phase antibodies) are the first to appear in the course of infection. They can be detected on day 7 or later (i.e., after 12 days of infection at the earliest). They persist for different periods for many weeks, although their level gradually decreases.
On the other hand, the IgG class of antibodies appears after 7 days from infection. They persist longer than IgM antibodies, and it is now believed that they can protect most people from the next SARS-CoV-2 infection. This opinion is based on an analogy with other viruses in this group. Unfortunately, it is not established yet, for how long antibodies can protect you from the next infection.
It is important to remember that whether your antibody test is negative or positive, you still should do an RT-PCR test to confirm or exclude past or present infection.
The antibody test result should be consulted with a doctor.
Where can you perform an antibody test in Warsaw?
The following antibody tests are available in Damiana Medical Center Warsaw
- Quantitative test for IgM antibodies against SARS-Cov-2
- Quantitative test for IgG antibodies against SARS-Cov-2
The sample material is venous blood. The specimens are taken at all Damian Medical Centre testing sites during opening hours. We kindly inform you that the best time to do an antibody test is between 12:30 a.m. and 2:30 p.m.
List of Testing Centers
Recommendations of the Damiana Medical Centre regarding different types of serological tests
- Rapid Test Cassette - from either capillary or whole blood
They are produced by many companies unknown in Poland and they have not been validated in Poland. Until the diagnostic reliability improves, the use of the qualitative Rapid Test Cassette (immunochromatographic) tests for anti-SARS-CoV-2 antibodies is not recommended. Therefore, the DMC Medical Department does not recommend these tests, cannot indicate any company whose tests would be qualitatively better than others, and does not take responsibility for the interpretation of their results.
- Blood tests using the immunoenzymatic ELISA or chemiluminescence method from blood or plasm
Tests of confirmed laboratory quality are venous blood tests by immunoenzymatic (ELISA) or chemiluminescence method performed in certified laboratories. DMC Medical Department confirms that the presence of IgG anti-SARS-CoV-2 antibodies diagnosed with these tests in combination with a negative RT-PCR molecular test result can be the basis for determining antibody production, prior infection, healing, and the current absence of infection.
Interpretation of serological tests
- IgM (-), IgG (-): no antibodies produced against SARS-CoV-2 - no current infection, or an asymptomatic infection phase not excluded,
- IgM (+), IgG (-): no anti-SARS-CoV-2 antibodies in IgG class; present IgM antibodies that may indicate current infection - likely ongoing coronavirus infection. Necessary sick leave and social isolation as well as performing the RT-PCR test - in the case of a positive result, information should be sent to the Poviat Sanitary and Epidemiological Station competent for the patient's place of residence for quarantine,
- IgM (-), IgG (+): quite high probability of past and completed infection. There are no indications of social isolation and sick leave. To ensure the absence of infection, it is necessary to perform an RT-PCR test - in the case of a positive RT-PCR result, information should be sent to the Poviat Sanitary and Epidemiological Station competent for the patient's place of residence for quarantine.
In the case of positive or doubtful results, it is recommended to visit or contact a GP via a teleconsultation to discuss the results of the tests and further proceedings.