COVID-19 Antibody Screening

COVID-19 Antibody Screening 

This blood test checks for a type of antibody called immunoglobulin G (IgG) that is the result of past or recent exposure to COVID-19, also known as the novel coronavirus (this is not a test for an active infection).

The human body produces IgG antibodies as part of the immune response to the virus. It usually takes around 10 to 18 days after being infected to produce enough antibodies to be detected in the blood.  

This test does not require fasting and is only available for persons 18 years of age or older. 

Why Get Screened?

According to the Centers for Disease Control (CDC), antibody testing should not be used to determine if an individual is immune 

You can help Colorado’s health officials understand the following by getting screened: 

  • Antibody testing can help to determine the proportion of a population that was previously infected with COVID-19.
  • Provide information about who may qualify as potential donors for convalescent plasma (the process of donating blood from those that have recovered from COVID in hopes that their antibodies may help those that are extremely sick from COVID recover). 
  • With continued research, antibody testing may help health officials identify community infection rates to understand how fast and where it is spreading as well as develop ways to decrease the spread of the virus. 

Who Should Get Screened?

    • People that have had a confirmed test of having COVID-19 
    • People that have been exposed to areas or institutions experiencing outbreaks 
    • Someone that had symptoms consistent with the virus may want to get screened to determine if they have developed antibodies. This will not tell you if you have immunity to the virus. 

Understanding COVID Antibody Results

There is a high level of false-positive results with antibody testing in people that have not been exposed, have not 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 there is a higher level of false-positive results
    • A second test may be necessary to confirm positive results

Positive results:   

A positive test result shows you may have antibodies from an infection with the virus that causes COVID-19. However, theres a chance a positive result means that you have antibodies from an infection with a virus from the same family of viruses (called coronaviruses), such as the one that causes the common cold.  

  • A positive result does NOT guarantee immunity and should not be viewed as protection against the virus. It is unknown at this time how much protection antibodies may provide and how long this protection may last.  
  • Talk with your healthcare provider about your test result and the type of test you took to understand what your result means.   
  • You should continue to practice recommended precautions such as wearing a mask in public places, social distancing, not touching your face, and washing your hands frequently to help protect yourself and others. 

Don’t have a doctor? You can always talk to a 9Health medical professional about your test results or other concerns. Just call us at 800-332-3078, ext. 2005 to leave a message and receive a call back within 24 hours.  

Negative results: 

A negative result means you may not have ever had COVID-19 or you have not developed antibodiesIt generally takes 10-18 days to develop antibodies after being exposed.   

  • It’s possible you could still get sick if you have been exposed to the virus recently. This means you could still spread the virus. 
  • Some people may take even longer to develop antibodies, and some people who are infected may not ever develop antibodies. 
  • Talk with your healthcare provider about your test result and the type of test you took to understand what your result means. 
  • You should continue to practice recommended precautions such as wearing a mask in public places, social distancing, not touching your face, and washing your hands frequently to help protect yourself and others. 

Don’t have a doctor? You can always talk to a 9Health medical professional about your test results or other concerns. Just call us at 800-332-3078, ext. 2005 to leave a message and receive a call back within 24 hours.  

A positive result does NOT guarantee immunity and should not be viewed as protection against the virus. 

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 quality validation. Learn More

In addition, persons being tested should have previously had a positive COVID test, or previously had COVID type symptoms or was exposed to areas or facilities with outbreaks 

This test is only for those who are NOT currently experiencing COVID-19 symptoms and have not experienced any symptoms with in the last 10 days. Common symptoms include but are not limited to, fever, cough, shortness of breath or difficulty breathing, and chills. Call your health care provider immediately if you are experiencing symptoms. For more information on symptoms visit the CDC website. 

Additional Resources

CDC Antibody Test Guidelines