COVID-19 Antibody Test (Blood)


The COVID-19 Antibody test checks for antibodies to COVID-19. If you've been exposed to COVID-19, your body produces antibodies as part of the immune response to the virus. This test cannot tell you if you have an active infection.

It can take 1 to 3 weeks after the exposure to the virus to develop antibodies.  At this time, it is unknown for how long antibodies persist following infection and if the presence of antibodies confers protective immunity.

FDA Guidance: Antibody testing can play a critical role in the fight against COVID-19. It can help identify individuals who may have been exposed to COVID-19 and have developed an immune response. Using antibody tests and clinical follow-up can also provide more information on immunity against COVID-19 for research and medical developments for the virus.

Having antibodies usually gives immunity from further infection. However, there is not enough evidence at this time to suggest that people who have these antibodies are protected against future COVID-19 infection. Experience with other viruses suggests that individuals who have antibodies may be able to resume work and other daily activities in society, as long as they are recovered and not currently infected with the virus.

This test has not been FDA cleared or approved. This test has been validated but FDA’s independent review of this validation is pending. This test is provided in compliance with FDA policy “Policy for Coronavirus Disease-2019 Tests During the Public Health Emergency (Revised).” Results from antibody testing should not be used to diagnose or exclude acute SARS-CoV-2 infection.

Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E.

Negative results do not preclude acute SARS-CoV-2 infection. If acute infection is suspected, direct testing for SARS-CoV-2 is necessary.



People with COVID-19 have a wide range of symptoms – ranging from mild symptoms to severe illness. Symptoms may appear 2-14 days after exposure to the virus. People with these symptoms may have COVID-19.

  • Fever or Chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore Throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea
This list does not include all possible symptoms. For more information on symptoms, visit Centers for Disease Control and Prevention (CDC)

This test may be right for you if you:

  • Have been diagnosed with COVID-19, it has been at least 10 days since your diagnosis, and you want to know if you have antibodies.
  • Have not had symptoms and have not had a known exposure to COVID-19 within the last 10 days but want to see if you have antibodies.
  • Have had or suspect you've had COVID-19 but have not experienced any new symptoms in the past 10 days.
  • Have had or suspect you've had COVID-19 but have not experienced a fever in the past 24 hours.

This test may NOT be right for you if you:

  • Are feeling sick or have had a fever within the last 24 hours.
  • Are trying to diagnose COVID-19.
  • Have been diagnosed with COVID-19 less than 10 days ago.
  • Were directly exposed to COVID-19 in the past 14 days.
  • Have a condition that weakens your immune system.

Results are for the detection of SARS CoV-2 antibodies. IgG antibodies to SARS-CoV-2 are generally detectable in blood 1 to 3 weeks after initial infection, although the duration of time antibodies are present post-infection is not well characterized. Individuals may have detectable virus present for several weeks following seroconversion.

Laboratories within the United States and its territories are required to report all positive results to the appropriate public health authorities.

Positive results suggest that you've been exposed to SARS-CoV-2 (COVID-19). Antibodies typically suggest protective immunity from further infection. However, evidence is still being collected to determine if antibodies provide protective immunity against SARS-CoV-2 (COVID-19) specifically.

Negative results do not preclude acute SARS-CoV-2 infection. If acute infection is suspected, direct testing for SARS-CoV-2 is necessary.

False positive results for SARS-CoV-2 IgG Ab ELISA may occur due to cross-reactivity from pre-existing antibodies or other possible causes.

False negative results may occur when getting an antibody test too soon after being infected. Additionally, some individuals who are infected with COVID-19 may not develop detectable levels of antibodies, such as those with weakened immune systems due to a medical condition or certain medications.


An antibody test may detect antibodies from previous exposure to coronaviruses other than COVID-19, which can cause a false positive result. Getting an antibody test too soon after being infected may cause a false negative result. Additionally, some individuals who are infected with COVID-19 may not develop detectable levels of antibodies, such as those with weakened immune systems due to a medical condition or certain medications.