Skip to main content

Serology Testing FAQs

Serology testing can check for different types of antibodies developed after exposure to the SARS-CoV-2 virus that causes COVID-19. Unlike PCR tests, serology tests by themselves, are of limited value in the immediate diagnosis of a patient where COVID-19 infection is suspected.

The test is designed to detect antibodies in a blood sample that would indicate that you have been previously infected by SARS-CoV-2 virus. However, antibodies may not be detected until 10-14 days following infection.

Serology tests may detect different types of antibodies. A positive result from an appropriately validated serology test indicates that someone currently has or has previously had COVID-19. However, a serology test may yield a negative test result even in infected patients (e.g., if antibody has not yet developed in response to the virus) or may be falsely positive (e.g., if antibody to a coronavirus type other than the current pandemic novel strain is present). Antibody tests by themselves cannot establish the immediate diagnosis of COVID-19. Serology testing cannot detect or rule out the presence of the virus.

Serology tests, when used broadly, can also be useful in understanding how many people have been infected or exposed and how far the pandemic has progressed.

Using this type of test on many patients may help the medical community to better understand how the immune response against the SARS-CoV-2 virus develops in patients over time and may provide guidance in infection control, exposure risk assessment, social distancing, and other population surveillance and preventive efforts.

Serology tests can play a critical role in the fight against COVID-19 by helping healthcare professionals identify individuals who have been exposed to SARS-CoV-2 virus. In the future, this may potentially be used to help determine, together with other clinical data, whether these individuals may be less susceptible to infection. In addition, these test results can aid in determining who may donate convalescent plasma for possible treatment of those who are seriously ill from COVID-19.