Mayo Clinic Laboratories offers a variety of serology tests to identify the presence of an antibody immune response to SARS-CoV-2, the virus that causes COVID-19. The following addresses some of the most frequently asked questions about this testing.
Q: Does Mayo Clinic Laboratories currently offer a test to detect COVID-19 infection?
A: Yes, Mayo Clinic Laboratories’ testing can be used to detect IgG and total (IgM/IgG/IgA) antibodies against SARS-CoV-2. This testing is only advised to be performed on individuals at least 10 days after initial symptom onset or at least 10 days after initial known exposure. This is because antibodies to SARS-CoV-2 develop approximately 8 to 11 days post-symptom onset (seroconversion) for the majority of patients. The presence of SARS-CoV-2 antibodies indicates that the patient has been exposed to COVID-19.
Q: What is antibody testing?
A: Antibody testing, also known as serologic testing, is used to detect antibodies in a patient’s blood specimen (serum). Antibodies are produced by the immune system in response to an infection. The presence of antibodies indicates that an individual has been infected with that particular infectious agent. These antibodies can be detected in some cases for years after the individual has recovered from the infection and will also be present if the patient was never even symptomatic. Serologic tests detect antibodies against infectious agents in serum and are a marker of an immune response to infection.
Q: Who can order this test?
A: The full menu of COVID-19 serology tests is available to order by all Mayo Clinic Laboratories clients. Three types of antibody tests are currently offered:
SARS-CoV-2 anti-RBD total antibody tests
These tests detect total antibodies against the SARS-CoV-2 receptor binding domain (RBD) and will be positive following natural infection or after vaccination, but will not differentiate between the two events
SARS-CoV-2 anti-NC Total Antibody Tests on serum
SARS-CoV-2 Multi-Antigen IgG Antibody Testing on Dried Bloods
Q: Will this test detect antibodies in everyone who has had COVID-19?
A: IgG or total antibodies to SARS-CoV-2 develop approximately 8 to 11 days post-symptom onset (seroconversion) for the majority of patients. Some individuals may develop antibodies after this time frame, while others, particularly those who are immunosuppressed, may never develop a detectable immune response.
Q: Should this test be used to diagnose patients suspected of currently having COVID-19?
Mayo Clinic Laboratories offers serology testing only as a means to detect antibodies to the virus, not to diagnose recent or active infection. We are focusing on correct diagnostic test stewardship and utilization. Symptomatic patients should be tested using PCR testing (Mayo ID: COVOO), not serology testing.
Q: What does detection of antibodies against SARS-CoV-2 mean for a patient?
Detection can indicate:
Q: Is Mayo Clinic Laboratories developing a test to detect IgM and IgA antibodies against the virus?
Although IgM and IgA antibodies against the virus may be detected sooner than IgG antibodies, we will not be offering this testing for the following reasons: