What is COVID-19?
COVID-19 is caused by the SARS-CoV-2 virus. This virus, which can cause mild to severe respiratory illness, has spread globally, including to the United States. There is limited information available to fully describe the different types of clinical illness associated with COVID-19. This illness likely spreads to others when a person shows signs or symptoms of being sick (e.g., fever, coughing, difficulty breathing, etc.) or in the few days leading up to symptoms.
What is the COVID-19 Antibody test?
The test is designed to detect antibodies (also known as immunoglobulins) against the virus that causes COVID-19. Antibodies are proteins produced by the immune system in response to an infection and are specific to that particular infection. They are found in the liquid part of blood specimens which is called serum or plasma, depending on the presence of clotting factors. Today your sample will be tested for immunoglobulin G (IgG).
This test detects IgG antibodies that develop in most patients within seven to 10 days after symptoms of COVID-19 begin. IgG antibodies remain in the blood after an infection has passed. These antibodies indicate that you may have had COVID-19 in the recent past and have developed antibodies that may protect you from future infection. It is unknown at this point how much protection antibodies might provide against another infection with SARS-CoV-2.
What are the known and potential risks and benefits of the test?
Potential risks include:
- Possible discomfort, bruising, infection or other complications that can happen during sample collection. Serious complications are very rare.
- Possible incorrect test result (see below for more information).
Potential benefits include:
- The results, along with other information, can help your health care provider make informed recommendations about your care.
- The results of this test may help limit the spread of COVID-19 to your family and others in your community.
What does it mean if I have a positive test result?
If you have a positive test result (antibodies are detected), you may have been infected with the virus that causes COVID-19 at some point in the past. There is still a chance that the antibodies indicate past infection due to other coronaviruses. These other coronaviruses cause the common cold. There is also a small chance that a positive result is incorrect (false positive).
The presence of IgG suggests that the infection happened weeks to months in the past. It also suggests that you may no longer be infectious. IgG indicates that you may have some immunity to the virus, though you may not. How much it might protect you from getting sick with COVID-19 in the future is unknown.
Your health care provider will work with you to determine how best to care for you based on the test results along with other factors of your medical history, including any previous symptoms, possible exposure to COVID-19 and the location of places you have recently traveled.
What does it mean if I have a negative test result?
A negative test result means that the antibodies to the virus that causes COVID-19 were not found in your sample. Some health conditions might make it difficult for your body to produce antibodies to an infection. However, it is possible for this test to give a negative result that is incorrect (false negative) in some people.
A negative result may occur if you are tested early in your illness and your body hasn’t had time to produce antibodies to infection. This means that you could possibly still have COVID-19 even though the test is negative. If this is the case, your health care provider will consider the test result together with all other aspects of your medical history (such as symptoms, possible exposures and geographical location of places you have recently traveled) in deciding how to care for you.
It is important that you work with your health care provider to help you understand the next steps you should take.