COVID-19 Antibody Screening FAQs
You may have experienced common symptoms of COVID-19, such as fever, cough, shortness of breath or you’ve been exposed to someone with COVID-19. Before you get tested, you may have questions about getting a COVID-19 Antibody Test. What is it? Why do I need to get tested? What will this tell me?
While the COVID-19 antibody tests from Quest Diagnostics provide high levels of both sensitivity and specificity (the ability to detect antibodies after a natural infection from COVID-19 and the ability to not find antibodies in someone that has not been infected with COVID-19), it is not yet well understood how this will relate to the level of antibodies our body makes after receiving the vaccine, and is not recommended to be used to determine immunity at this time until further post-vaccination testing has been studied.
Here are the answers to some frequently asked questions from people just like you!
What is a COVID-19 Antibody test?
This is a blood test (also known as serology or immune response test) that checks for a type of antibody called immunoglobulin G (IgG) that the body will produce as a result of past or recent exposure to COVID-19, also known as the novel coronavirus (this is not a test for an active infection).
How is the test performed?
It is a simple blood draw for those that are 18 years of age and older.
It does not require fasting
Why is this important?
This test may show if you had prior infection, whether or not you ever experienced symptoms of COVID-19. The human body produces IgG antibodies as part of the immune response to the virus.
What will it tell me?
According to the Centers for Disease Control (CDC), antibody testing should not be used to determine if an individual is immune, BUT it can offer information to help prevent the spread:
- Public health officials can use antibody status data to get a more accurate picture of the prevalence of COVID-19 around the world and in local communities. Understanding the true reach of the virus is key to slowing its spread.
- For yourself, knowing your own antibody status means you can alert your family and friends of your previous exposure and recommend they get tested if you have been in close contact with them.
- Antibody status also helps give you and your healthcare provider information about possibly returning to work, school, or other activities.
Who should get screened?
People that have had a confirmed test of having COVID-19, or people that have been exposed to areas or institutions experiencing outbreaks may want to see if they have developed antibodies.
If you had symptoms consistent with the virus, you may want to get screened to determine if you have developed antibodies. This will not tell you if you have immunity to the virus.
I've heard about false positive/negative results, what does this mean?
There is a high level of false-positive results with antibody testing in people that have not been exposed, have tested positive for the virus, or have not had COVID–like symptoms.
- This test can sometimes detect antibodies from other coronaviruses, which can cause a false-positive result if you have been previously diagnosed with or exposed to other types of coronaviruses. Additionally, if you test too soon, your body may not have produced enough IgG antibodies to be detected by the test yet, which can lead to a false-negative result.
- Areas, where there is a high level of prevalence of the virus, have a higher likelihood that persons with a positive antibody test are truly positive
- Areas, where there is a low prevalence of the virus, have a higher level of false-positive results
- A second test may be necessary to confirm positive results
What do the results mean?
A positive result may tell you if you have been exposed to the COVID-19 virus. A positive result means your body has developed antibodies to COVID-19. It does NOT guarantee immunity and should not be viewed as protection against the virus. More research is needed to determine the level and length of time of immunity a person may have against the virus.
A negative result means you have not developed antibodies to COVID-19. It generally takes 10-18 days to develop antibodies after being exposed.
How is this test different than those offered by others?
The CDC recommends that testing be performed that provides a high level of positive predictive value (PPV) and negative predictive value (NPV). This means that the probability that individuals with a positive test are truly antibody positive and individuals with negative test results are truly antibody negative.
To do this, the test being used should have a high level of sensitivity and specificity, meaning it reliably measures for COVID-19. In partnership with Quest Diagnostics, the tests used to provide high levels of both sensitivity and specificity and have demonstrated significant validation. Learn More
In addition, persons being tested should have previously had a positive COVID test, have previously had COVID type symptoms, or were exposed to areas or facilities with outbreaks.
Regardless of your antibody testing result, it is important to follow the latest guidelines set by your community and the CDC to help slow the spread of the virus. For more information about COVID-19 please visit the CDC website.