Antibody (serology) testing is generally limited to the following cases:
- Patients with suspected multisystem inflammatory syndrome (MIS) due to COVID-19 infection
- For public health investigation of complicated COVID-19 case transmissions
- In patients with severe illness who have repeatedly received a negative lab PCR test result
Antibody testing results cannot tell the difference between those who are vaccinated or previously infected with COVID-19. Positive antibody test results will only show that you've either been exposed to COVID-19 OR vaccinated OR both. It cannot tell you if you are protected from COVID-19.
Additionally:
- Antibody levels decline over time, so an individual may have no measurable antibodies despite having been previously infected.
- Even with antibodies, individuals can still be re-infected with COVID-19 and capable of transmitting the virus to others.