COVID-19 Antibody Testing

Intermountain Healthcare is using a COVID-19 antibody test authorized for use by the FDA that may help identify previous COVID-19 infections. The antibody test works by taking a blood sample to see if an individual has developed antibodies to SARS-CoV-2, the virus that causes COVID-19. The blood test is performed on carefully selected Intermountain patients and caregivers who meet specific criteria. The FDA is permitting antibody test development through a formal emergency use authorization (EUA) process and making available approved tests to health systems and members of the public across the U.S. The use of the test in this way will increase knowledge about the test. Intermountain is committed to keeping caregivers, patients, and our communities informed about what we know and don’t know currently about antibody testing.

Frequently Asked Questions

What are the differences between COVID-19 nasal testing and COVID-19 antibody (serologic) testing?

The standard nasal testing will continue to be the first line of testing for the general public. The nasal swab test is used to identify if a person has, or does not have, COVID-19 in their nose on the day the person is sampled. The antibody test works by taking a blood sample from an individual who has developed antibodies to SARS-CoV-2, the virus that causes COVID-19, to identify pasts infection with the virus. Both types of tests have limitations. The standard nasal swab test does not determine if the patient has had COVID-19 at any time prior to the test. Antibody testing by itself will not reliably identify individuals who are currently infected with COVID-19. 

Why is Intermountain offering antibody testing?

The nasal swab test can identify persons who need to be isolated or quarantined and it can be used to help control spread of the disease by keeping infected patients isolated so that they don’t spread the virus to others. The primary objective of antibody testing is to assess whether an individual may have been previously infected with the virus. At this time, antibody results should not be used to guide or change recommendations on social distancing, personal protection (face covers and masking), or work-related policies. How we use the results of the antibody test will likely change and evolve as we learn more about how the antibody result predicts immunity against COVID-19.

When used appropriately, use of the antibody test can help us better understand the extent and spread of COVID-19 in a certain population and identify risk factors for infection. Widespread, community-based antibody testing should only be done in collaboration with trained epidemiologists and researchers. In addition, Intermountain has identified specific criteria in which antibody testing can assist in the clinical management of patients with COVID 19 symptoms, identify asymptomatic transmission after high risk exposures, and identify past COVID 19 infection in patients with a history of a compatible syndrome. See below for specific criteria. 

What does a positive antibody test result mean?

  • The individual was previously infected with or exposed to COVID-19.
  • The individual’s body has produced a measurable antibody response to COVID-19.
  • A positive test can also represent a false positive.
  • A positive test does not mean the individual is immune to COVID-19.
  • A positive test does not mean the individual can’t be reinfected with COVID-19 and spread it to others.
  • NOTE: any antibody test result should not be used to guide or change recommendations on social distancing, personal protection (face covers and masking), or work-related policies.

What does a negative antibody test mean?

  • There is no evidence the individual had a past COVID-19 infection. If symptoms are still present, or cleared up less than two weeks prior, it may be too early to detect antibodies.
  • The negative antibody result can’t be used to rule out current or asymptomatic (showing no symptoms) COVID-19 infection.
  • It’s unclear if asymptomatically infected individuals develop any detectable antibody.
  • If you are immunocompromised, you may not create adequate or detectable antibodies.
  • NOTE: any antibody test result should not be used to guide or change recommendations on social distancing, personal protection (face covers and masking), or work-related policies.

Who should get an antibody test?

Limited testing availability requires antibody testing to be prioritized for individuals where a positive result would support care decisions or patient isolation and public health actions:

  • Hospitalized patients with signs and symptoms of COVID-19 for at least 8 days AND a negative nasal swab test will be prioritized first for antibody testing.
  • Healthcare workers and individuals with high-risk, unprotected exposures to known COVID-19 patients may also qualify for antibody testing. Testing should be performed at least 14 days after exposure to an infected patient. A household contact of a COVID-19-infected patient (confirmed from a positive nasal swab test) would be an example of a high-risk exposure.
  • Healthcare workers and individuals who had a respiratory tract infection consistent with COVID-19 after December 1, 2019 that was previously undiagnosed may qualify if a positive antibody testing result would support care decisions.

How can someone get antibody testing?

Individuals can contact their primary care provider to find out if they meet specific criteria for antibody testing.